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Using log analysis to drive experiments and win the AWS DeepRacer F1 ProAm Race

This is a guest post by Ray Goh, a tech executive at DBS Bank.  AWS DeepRacer is an autonomous 1/18th scale race car powered by reinforcement learning, and the AWS DeepRacer League is the world’s first global autonomous racing league. It’s a fun and easy way to get started with machine learning (ML), regardless of […]

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This is a guest post by Ray Goh, a tech executive at DBS Bank. 

AWS DeepRacer is an autonomous 1/18th scale race car powered by reinforcement learning, and the AWS DeepRacer League is the world’s first global autonomous racing league. It’s a fun and easy way to get started with machine learning (ML), regardless of skill or background. For companies, it’s also a powerful platform to facilitate teaching ML to employees at the enterprise level.

As part of our digital transformation journey at DBS Bank, we’re taking innovative steps to future-proof our workforce. We’ve partnered with AWS to bring the AWS DeepRacer League to DBS to train over 3,000 employees in AI and ML by the end of 2020. Thanks to the AWS DeepRacer virtual simulation and training environment, our employees can upgrade their skills and pick up new knowledge, even when they aren’t physically in the office. The ability to run private races also allows us to create our own racing league, where our employees can put their newly learned skills to the test.

Winning the F1 ProAm Race in May 2020

As an individual racer, I’ve been active in the AWS DeepRacer League since 2019. In May 2020, racers from around the world had the unique opportunity to pit their ML skills against F1 professionals in the AWS DeepRacer F1 ProAm Race. We trained our models on a replica of the F1 Spanish Grand Prix track, and the top 10 racers from the month-long, head-to-head qualifying race faced off against F1 professional drivers Daniel Ricciardo and Tatiana Calderon in a Grand Prix-style race. Watch the AWS DeepRacer ProAm series here.

After a challenging month of racing, I emerged as the champion in the F1 ProAm Race, beating fellow racers and the pro F1 drivers to the checkered flag! Looking back now, I attribute my win to having performed many experiments throughout the month of racing. Those experiments allowed me to continuously tweak and improve my model leading up to the final race. Behind those experiments are ideas that arose from data-driven insights through log analysis.

What is log analysis?

Log analysis is using a Jupyter notebook to analyze and debug models based on log data generated from the AWS DeepRacer simulation and training environment. With snippets of Python code, you can plot and visualize your model’s training performance through various graphs and heatmaps. I created several unique visualizations that ultimately helped me train a model that was fast and stable enough to win the F1 ProAm Race.

Figure 1 Log analysis visualizations

In this post, I share some of the visualizations I created and show how you can use Amazon SageMaker to spin up a notebook instance to perform log analysis using DeepRacer model training data.

If you’re already familiar with opening notebooks in a JupyterLab notebook application, you can simply clone my log analysis repository and skip directly to the log analysis section.

Amazon SageMaker notebook instances

An Amazon SageMaker notebook instance is a managed ML compute instance running the Jupyter notebook application. Amazon SageMaker manages the creation of the instance and its related resources, so we can focus on analyzing the data collected during training without worrying about provisioning Amazon Elastic Compute Cloud (Amazon EC2) or storage resources directly.

Using an Amazon SageMaker notebook instance for log analysis

One of the greatest benefits of using an Amazon SageMaker notebook instance to perform AWS DeepRacer log analysis is that Amazon SageMaker automatically installs Anaconda packages and libraries for common deep learning platforms on our behalf, including TensorFlow deep learning libraries. It also automatically attaches an ML storage volume to our notebook instance, which we can use as a persistent working storage to perform log analysis and retain our analysis artifacts.

Creating a notebook instance

To get started, create a notebook instance on the Amazon SageMaker console.

  1. On the Amazon SageMaker console, under Notebook, choose Notebook instances.
  2. Choose Create notebook instance.

  1. For Notebook instance name, enter a name (for example, DeepRacer-Log-Analysis).
  2. For Notebook instance type¸ choose your instance.

For AWS DeepRacer log analysis, the smallest instance type (ml.t2.medium) is usually sufficient.

  1. For Volume size in GB, enter your storage volume size. For this post, we enter 5.

When the notebook instance shows an InService status, we can open JupyterLab, the IDE for Jupyter notebooks.

  1. Locate your notebook instance and choose Open JupyterLab.

Cloning the log analysis repo from JupyterLab

From the JupyterLab IDE, we can easily clone a Git repository to use log analysis notebooks shared by the community. For example, I can clone my log analysis repository in seconds, using https://github.com/TheRayG/deepracer-log-analysis.git as the Clone URI.

After cloning the repository, we should see it appear in the folder structure on the left side of the JupyterLab IDE.

Downloading logs from the AWS DeepRacer console

To prepare the data that we want to analyze, we have to download our model training logs from the AWS DeepRacer console.

  1. On the AWS DeepRacer console, under Reinforcement learning, choose Your models.
  2. Choose the model to analyze.
  3. In the Training section, under Resources, choose Download Logs.

This downloads the training log files, which are packaged in a .tar.gz file.

Extracting the required log files for analysis

In this step, we complete the final configurations.

  1. Extract the RoboMaker and Amazon SageMaker log files from the .tar.gz package (found in the logs/training/ subdirectory).

  1. Upload the two log files into the /deepracer-log-analysis/logs folder in the JupyterLab IDE.

We’re now ready to open up our log analysis notebook to work its magic!

  1. Navigate to the /deepracer-log-analysis folder on the left side of the IDE and choose the .ipynb file to open the notebook.
  2. When opening the notebook, you may be prompted to provide a kernel. Choose a kernel that uses Python 3, such as conda_tensorflow_p36.

  1. Wait until the kernel status changes from Starting to Idle.
  2. Edit the notebook to specify the path and names of the two log files that we just uploaded.

To perform our visualizations, we use the simulation trace data from the RoboMaker log file and policy update data from the Amazon SageMaker log file. We parse the data in the notebook using pandas dataframes, which are two-dimensional labeled data structures like spreadsheets or SQL tables.

For the RoboMaker log file, we aggregate important information, such as minimum, maximum, and average progress and lap completion ratios for each iteration of training episodes.

For the Amazon SageMaker log file, we calculate the average entropy per epoch in each policy update iteration.

Performing visualizations

We can now run the notebook by choosing Run and Run All Cells in JupyterLab. My log analysis notebook contains numerous markdown descriptions and comments to explain what each cell does. In this section, I highlight some of the visualizations from that notebook and explain some of the thought processes behind them.

Visualizing the performance envelope of the model

A common question asked by beginners of AWS DeepRacer is, “If two models are trained for the same amount of time using the same reward function and hyperparameters, why do they have different lap times when I evaluate them?”

The following visualization is a great way to explain it; it shows the frequency of performance to lap time in seconds.

I use this to illustrate the performance envelope of my model. We can show the relative probability of the model achieving various lap times by plotting a histogram of lap times achieved by the model during training. We can also work out statistically the average and best-case lap times that we can expect from the model. I’ve noticed that the lap times of the model during training resembles a normal distribution, so I use the -2 and -3 Std Dev markers to show the potential best-case lap times for the model, albeit with just 2.275% (-2 SD) and 0.135% (-3 SD) chance of occurring respectively. By understanding the likelihood of the model achieving a given lap time and comparing that to leaderboard times, I can gauge if I should continue cloning and tweaking the model, or abandon it and start fresh with a different approach.

Identifying potential model checkpoints for race submission

When training many different models for a race, racers commonly ask, “Which model would give me the highest chance of winning a virtual race?”

To answer that question, I plot the top quartile (p25) lap times vs. iterations from the training data, which identifies potential models for race submission. This scatter plot also allows me to identify potential trade-offs between speed (dots with very fast lap times) and stability (dense cluster of dots for a particular iteration). From the following diagram, I would choose models from the three highlighted iterations for race submission.

Identifying convergence and gauging consistency

As racers gain experience with model training, they start paying attention to convergence in their models. Simply put, convergence in the AWS DeepRacer context is when a model is performing close to its best (in terms of average lap progress), and further training may harm its performance or make it overfit, such that it only does well for that track in a very specific simulation environment, but not in other tracks or in a physical AWS DeepRacer car. That begs the following questions: “How do I tell when the model has converged?” and “How consistent is my model after it has converged?”

To aid in visualizing convergence, I overlay the entropy information from the Amazon SageMaker policy training logs over the usual plots for rewards and progress.

Entropy is a measure of the amount of randomness in our reinforcement learning neural network. At the beginning of model training, entropy is high, because our neural network is updated mostly based on random actions as the car explores the track.

Over time, with more experiences gained from actions and rewards at various parts of the track, the car starts to exploit this information and takes less random actions.

The thinking behind this is that, as rewards and progress increase, the entropy value should decrease. When rewards and progress plateau, the entropy loss should also flatten out. Therefore, I use entropy as an additional indicator for convergence.

To gauge the consistency of my model, I also plot the percentage of lap completions per iteration during training. When the model is capable of completing laps, the percentage of completed laps should creep up in subsequent iterations, until around the point of convergence, when the percentage value should plateau too. See the following plot.

The model training process is probabilistic because the reinforcement learning agent incorporates entropy to explore the environment. To smooth out the effects of the probabilistic model in my visualization, I use a simple moving average over three iterations for each of my plotted metrics.

Identifying inefficiencies in driving behavior

When racers have a competitive model, they may start to wonder, “Are there sections of the track where the car is driving inefficiently? What are the sections where I can encourage the car to speed up?”

In pursuit of answering these questions, I designed a visualization that shows the average speed and steering angle of the car measured at every waypoint along the track. This allows me to see how the model is negotiating the track, because from this plot, you can see the rate at which the model is speeding up or slowing down as it travels through the waypoints. The following visualization shows the deviation of the optimal racing line (orange) from the track centerline (blue).

You can also see how the model adjusts its steering angle as it negotiates turns. What I love about the following visualization is that it allows me to see clearly at which point after a long straight the model starts to brake before entering into a turn. It also helps me visualize if a model is accelerating quickly enough upon exiting a turn.

Identifying track sections to adjust actions and rewards

Although speed is the primary performance criteria in a time trial race, stability is also important in an object avoidance or head-to-head race. Because time penalties for going off-track impact race position, it’s very important to find the right balance between speed and stability. Even if the model can negotiate the track well, top racers are also asking, “Is the car over- or under-steering at any of the turns? Which turn should I focus on optimizing in subsequent experiments?”

By plotting a heatmap of rewards over the track, you can easily see how consistently we reward the model at various parts of the track. A thin band in the heatmap reflects very consistent rewards, while a sparse scattering of dots brings attention to the parts of the track where the model has trouble getting rewards. For my reward function, this usually highlights the turns at which the model is over- or under-steering.

For example, in the highlighted parts of the preceding plot, the model isn’t consistently going around those turns according to the racing line that I’m rewarding for. It’s actually over-steering as it exits Turn 3 (around waypoint 62), and under-steering around the other two highlighted turns. Tweaking the action space may help (in the case of under-steering, lowering the speed at high steering angles). Interestingly, the lap completion rate of the model can increase substantially with such minor tweaks, without sacrificing lap times!

Experiment, Experiment, Experiment

For the F1 ProAm Race that in May 2020, I planned to do two experiments per day (at least 60 experiments total) to try out different reward strategies and racing lines. I could iterate quickly while focusing on incremental improvements by using log analysis to surface insights from the training data.

For example, the following plot helped me answer the question “Is the car going to go as fast as possible through the entire lap?” by showing where the car uses 0-degree and highest speeds.

Cleaning up

To save on ML compute costs, when you’re done with log analysis, you can stop the notebook instance without deleting it. The notebook, data, and log files are still retained as long as you don’t delete the notebook instance. A stopped instance still incurs cost for the provisioned ML storage. But you can always restart the instance later to continue working on the notebook.

When you no longer need the notebook or data, you can permanently delete the instance, which also deletes the attached ML storage volume, so that you no longer incur its related ML storage cost.

For pricing details for Amazon SageMaker notebook instances, see Amazon SageMaker Pricing.

Conclusion

The visualizations I shared with you in this post helped me win the May 2020 F1 ProAm Race against other top racers and F1 pros, so it’s my hope that by sharing these ideas with the community, others can benefit and learn from them too.

Together as a community of practice, we can help to accelerate learning for everyone and raise the bar for the AI/ML community in general!

You can start training your own model and improve it through log analysis by signing in to the AWS DeepRacer console.


About the Author

Ray Goh is a Tech executive who leads Agile Teams in the delivery of FX Trading & Digital Solutions at DBS Bank. He is a passionate Cloud advocate with deep interest in Voice and Serverless technology, and has 8 AWS Certifications under his belt. He is also active in the DeepRacer (a Machine Learning autonomous model car) community. Obsessed with home automation, he owns close to 20 Alexa-enabled devices at home and in the car.

Source: https://aws.amazon.com/blogs/machine-learning/using-log-analysis-to-drive-experiments-and-win-the-aws-deepracer-f1-proam-race/

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How to Get the Best Start at Sports Betting

If you are looking into getting into sports betting, then you might be hesitant about how to start, and the whole idea of it can be quite daunting. There are many techniques to get the best possible start at sports betting and, in this article, we will have a look at some of the best […]

The post How to Get the Best Start at Sports Betting appeared first on 1redDrop.

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If you are looking into getting into sports betting, then you might be hesitant about how to start, and the whole idea of it can be quite daunting. There are many techniques to get the best possible start at sports betting and, in this article, we will have a look at some of the best tips for that.

Mental preparation

This sounds a bit pretentious, but it is very important to understand some things about betting before starting so you can not only avoid nasty surprises but also avoid losing too much money. Firstly, you need to know that, in the beginning, you will not be good at betting. It is through experience and learning from your mistakes that you will get better. It is imperative that you do not convince yourself that you are good at betting, especially if you win some early bets, because I can guarantee it will have been luck – and false confidence is not your friend. 

It is likely that you will lose some money at first, but this is to be expected. Almost any hobby that you are interested in will cost you some money so, instead, look at it as an investment. However, do not invest ridiculous amounts; rather, wait until you are confident in your betting ability to start placing larger stakes. 

Set up different accounts

This is the best way to start with sports betting, as the welcome offers will offset a lot of the risk. These offers are designed to be profitable to entice you into betting with the bookie, but it is completely legal to just profit from the welcome offer and not bet with the bookie again. 

If you do this with the most bookies, as you can, you are minimising the risk involved with your betting and maximising possible returns, so it really is a no-brainer.

As well as this clear advantage, different betting companies offer different promotions. Ladbrokes offer a boost every day, for example, where you can choose your bet and boost it a little bit, and the Parimatch betting website chooses a bet for big events and doubles the odds. 

If you are making sure you stay aware of the best offers across these platforms, then you will be able to use the most lucrative ones and, as such, you will be giving yourself the best chance of making money. The house always wins, as they say, but if you use this tip, you are skewing the odds back in your favour. 

Remember, the house wins because of gamblers that do not put in the effort and do not bet smart. Avoid those mistakes and you will massively increase your chances of making money.

Tipsters

On Twitter, especially, but also other social media platforms, there are tipsters who offer their bets for free. It is not so much the bets themselves that you are interested in, but rather why they are betting on this. It is important that you find tipsters who know what they are doing, though, because there are a lot of tipsters who are essentially scamming their customers. It is quite easy to find legitimate tipsters because they are not afraid to show their mistakes. 

Once you have found good tipsters, then you need to understand the reasoning behind their bets. When you have done that, you can start placing these bets yourself, and they will likely be of better value since some tipsters influence the betting markets considerably. You can also follow their bets as they are likely to be sensible bets, although this does not necessarily translate to success.

Source: https://1reddrop.com/2020/10/20/how-to-get-the-best-start-at-sports-betting/?utm_source=rss&utm_medium=rss&utm_campaign=how-to-get-the-best-start-at-sports-betting

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Natural Language Processing in Production: 27 Fast Text Pre-Processing Methods

Estimates state that 70%–85% of the world’s data is text (unstructured data) [1]. New deep learning language models (transformers) have caused explosive growth in industry applications [5,6,11]. This blog is not an article introducing you to Natural Language Processing. Instead, it assumes you are familiar with noise reduction and normalization of text. It covers text preprocessing up […]

The post Natural Language Processing in Production: 27 Fast Text Pre-Processing Methods appeared first on TOPBOTS.

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text pre-processing

Estimates state that 70%–85% of the world’s data is text (unstructured data) [1]. New deep learning language models (transformers) have caused explosive growth in industry applications [5,6,11].

This blog is not an article introducing you to Natural Language Processing. Instead, it assumes you are familiar with noise reduction and normalization of text. It covers text preprocessing up to producing tokens and lemmas from the text.

We stop at feeding the sequence of tokens into a Natural Language model.

The feeding of that sequence of tokens into a Natural Language model to accomplish a specific model task is not covered here.

In production-grade Natural Language Processing (NLP), what is covered in this blog is that fast text pre-processing (noise cleaning and normalization) is critical.

  1. I discuss packages we use for production-level NLP;
  2. I detail the production-level NLP preprocessing text tasks with python code and packages;
  3. Finally. I report benchmarks for NLP text pre-processing tasks;

Dividing NLP Processing into Two Steps

We segment NLP into two major steps (for the convenience of this article):

  1. Text pre-processing into tokens. We clean (noise removal) and then normalize the text. The goal is to transform the text into a corpus that any NLP model can use. A goal is rarely achieved until the introduction of the transformer [2].
  2. A corpus is an input (text preprocessed into a sequence of tokens) into NLP models for training or prediction.

The rest of this article is devoted to noise removal text and normalization of text into tokens/lemmas (Step 1: text pre-processing). Noise removal deletes or transforms things in the text that degrade the NLP task model. It is usually an NLP task-dependent. For example, e-mail may or may not be removed if it is a text classification task or a text redaction task. We’ll cover replacement and removal of the noise.

Normalization of the corpus is transforming the text into a common form. The most frequent example is normalization by transforming all characters to lowercase. In follow-on blogs, we will cover different deep learning language models and Transformers (Steps 2-n) fed by the corpus token/lemma stream.

NLP Text Pre-Processing Package Factoids

There are many NLP packages available. We use spaCy [2], textacy [4], Hugging Face transformers [5], and regex [7] in most of our NLP production applications. The following are some of the “factoids” we used in our decision process.

Note: The following “factoids” may be biased. That is why we refer to them as “factoids.”

NLTK [3]

  • NLTK is a string processing library. All the tools take strings as input and return strings or lists of strings as output [3].
  • NLTK is a good choice if you want to explore different NLP with a corpus whose length is less than a million words.
  • NLTK is a bad choice if you want to go into production with your NLP application [3].

Regex

The use of regex is pervasive throughout our text-preprocessing code. Regex is a fast string processor. Regex, in various forms, has been around for over 50 years. Regex support is part of the standard library of Java and Python, and is built into the syntax of others, including Perl and ECMAScript (JavaScript);

spaCy [2]

  • spaCy is a moderate choice if you want to research different NLP models with a corpus whose length is greater than a million words.
  • If you use a selection from spaCy [3], Hugging Face [5], fast.ai [13], and GPT-3 [6], then you are performing SOTA (state-of-the-art) research of different NLP models (my opinion at the time of writing this blog).
  • spaCy is a good choice if you want to go into production with your NLP application.
  • spaCy is an NLP library implemented both in Python and Cython. Because of the Cython, parts of spaCy are faster than if implemented in Python [3];
  • spacy is the fastest package, we know of, for NLP operations;
  • spacy is available for operating systems MS Windows, macOS, and Ubuntu [3];
  • spaCy runs natively on Nvidia GPUs [3];
  • explosion/spaCy has 16,900 stars on Github (7/22/2020);
  • spaCy has 138 public repository implementations on GitHub;
  • spaCy comes with pre-trained statistical models and word vectors;
  • spaCy transforms text into document objects, vocabulary objects, word- token objects, and other useful objects resulting from parsing the text ;
  • Doc class has several useful attributes and methods. Significantly, you can create new operations on these objects as well as extend a class with new attributes (adding to the spaCy pipeline);
  • spaCy features tokenization for 50+ languages;

Do you find this in-depth technical education about NLP applications to be useful? Subscribe below to be updated when we release new relevant content.

Creating long_s Practice Text String

We create long_, a long string that has extra whitespace, emoji, email addresses, $ symbols, HTML tags, punctuation, and other text that may or may not be noise for the downstream NLP task and/or model.

MULPIPIER = int(3.8e3)
text_l = 300 %time long_s = ':( 😻 😈 #google +1 608-444-0000 08-444-0004 608-444-00003 ext. 508 '
long_s += ' 888 eihtg DoD Fee https://medium.com/ #hash ## Document Title</title> '
long_s += ':( cat- \n nip'
long_s += ' immed- \n natedly <html><h2>2nd levelheading</h2></html> . , '
long_s += '# bhc@gmail.com f@z.yx can\'t Be a ckunk. $4 $123,456 won\'t seven '
long_s +=' $Shine $$beighty?$ '
long_s *= MULPIPIER
print('size: {:g} {}'.format(len(long_s),long_s[:text_l]))

output =>

CPU times: user 3 µs, sys: 1 µs, total: 4 µs
Wall time: 8.11 µs
size: 1.159e+06 :( 😻 😈 #google +1 608-444-0000 08-444-0004 608-444-00003 ext. 508 888 eihtg DoD Fee https://medium.com/ #hash ## Document Title</title> :( cat- nip immed- natedly <html><h2>2nd levelheading</h2></html> . , # bhc@gmail.com f@z.yx can't Be a ckunk. $4 $123,456 won't seven $Shine $$beigh

A string, long_s of 1.159 million characters is created in 8.11 µs.

Python String Corpus Pre-processing Step and Benchmarks

All benchmarks are run within a Docker container on MacOS Version 14.0 (14.0).

Model Name: Mac Pro
Processor Name: 12-Core Intel Xeon E5
Processor Speed: 2.7 GHz
Total Number of Cores: 24
L2 Cache (per Core): 256 KB
L3 Cache: 30 MB
Hyper-Threading Technology: Enabled Memory: 64 GB

Note: Corpus/text pre-processing is dependent on the end-point NLP analysis task. Sentiment Analysis requires different corpus/text pre-processing steps than document redaction. The corpus/text pre-processing steps given here are for a range of NLP analysis tasks. Usually. a subset of the given corpus/text pre-processing steps is needed for each NLP task. Also, some of required corpus/text pre-processing steps may not be given here.

1. NLP text preprocessing: Replace Twitter Hash Tags

from textacy.preprocessing.replace import replace_hashtags
%time text = replace_hashtags(long_s,replace_with= 'HASH')
print('size: {:g} {}'.format(len(text),text[:text_l])))

output =>

CPU times: user 223 ms, sys: 66 µs, total: 223 ms
Wall time: 223 ms
size: 1.159e+06 :
( 😻 😈 _HASH_ +1 608-444-0000 08-444-0004 608-444-00003 ext. 508 888 eihtg DoD Fee https://medium.com/ _HASH_ ## Document Title</title> :( cat- nip immed- natedly <html><h2>2nd levelheading</h2></html> . , # bhc@gmail.com f@z.yx can't Be a ckunk. $4 $123,456 won't seven $Shine $$beigh

Notice that #google and #hash are swapped with_HASH_,and ##and _# are untouched. A million characters were processed in 200 ms. Fast enough for a big corpus of a billion characters (example: web server log).

2. NLP text preprocessing: Remove Twitter Hash Tags

from textacy.preprocessing.replace import replace_hashtags
%time text = replace_hashtags(long_s,replace_with= '')
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 219 ms, sys: 0 ns, total: 219 ms
Wall time: 220 ms
size: 1.1134e+06 :( 😻 😈 +1 608-444-0000 08-444-0004 608-444-00003 ext. 508 888 eihtg DoD Fee https://medium.com/ ## Document Title</title> :( cat- nip immed- natedly <html><h2>2nd levelheading</h2></html> . , # bhc@gmail.com f@z.yx can't Be a ckunk. $4 $123,456 won't seven $Shine $$beighty?$

Notice that #google and #hash are removed and ##,and _# are untouched. A million characters were processed in 200 ms.

3. NLP text preprocessing: Replace Phone Numbers

from textacy.preprocessing.replace import replace_phone_numbers
%time text = replace_phone_numbers(long_s,replace_with= 'PHONE')
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 384 ms, sys: 1.59 ms, total: 386 ms
Wall time: 383 ms
size: 1.0792e+06
:( 😻 😈 PHONE 08-PHONE 608-444-00003 ext. 508 888 eihtg

Notice phone number 08-444-0004 and 608-444-00003 ext. 508 were not transformed.

4. NLP text preprocessing: Replace Phone Numbers – better

RE_PHONE_NUMBER: Pattern = re.compile( # core components of a phone number r"(?:^|(?<=[^\w)]))(\+?1[ .-]?)?(\(?\d{2,3}\)?[ .-]?)?(\d{2,3}[ .-]?\d{2,5})" # extensions, etc. r"(\s?(?:ext\.?|[#x-])\s?\d{2,6})?(?:$|(?=\W))", flags=re.UNICODE | re.IGNORECASE) text = RE_PHONE_NUMBER.sub('_PHoNE_', long_s)
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 353 ms, sys: 0 ns, total: 353 ms
Wall time: 350 ms
size: 1.0108e+06 :( 😻 😈 _PHoNE_ _PHoNE_ _PHoNE_ 888 eihtg DoD Fee https://medium.com/ ## Document Title</title> :( cat- nip immed- natedly <html><h2>2nd levelheading</h2></html> . , # bhc@gmail.com f@z.yx can't Be a ckunk. $4 $123,456 won't seven $Shine $$beighty?$

Notice phone number 08-444-0004 and 608-444-00003 ext. 508 were transformed. A million characters were processed in 350 ms.

5. NLP text preprocessing: Remove Phone Numbers

Using the improved RE_PHONE_NUMBER pattern, we put '' in for ‘PHoNE' to remove phone numbers from the corpus.

text = RE_PHONE_NUMBER.sub('', long_s)
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 353 ms, sys: 459 µs, total: 353 ms
Wall time: 351 ms
size: 931000 :( 😻 😈 888 eihtg DoD Fee https://medium.com/ ## Document Title</title> :( cat- nip immed- natedly <html><h2>2nd levelheading</h2></html> . , # bhc@gmail.com f@z.yx can't Be a ckunk. $4 $123,456 won't seven $Shine $$beighty?$

A million characters were processed in 375 ms.

6. NLP text preprocessing: Removing HTML metadata

I admit removing HTML metadata is my favorite. Not because I like the task, but because I screen-scrape frequently. There is a lot of useful data that resides on an IBM mainframe, VAX-780 (huh?), or whatever terminal-emulation that results in an HTML-based report.

These techniques of web scraping of reports generate text that has HTML tags. HTML tags are considered noise typically as they are parts of the text with little or no value in the follow-on NLP task.

Remember, we created a test string (long_s) a little over million characters long with some HTML tags. We remove the HTML tags using BeautifulSoup.

from bs4 import BeautifulSoup
%time long_s = BeautifulSoup(long_s,'html.parser').get_text()
print('size: {:g} {}'.format(len(long_s),long_s[:text_l])))

output =>

CPU times: user 954 ms, sys: 17.7 ms, total: 971 ms
Wall time: 971 ms
size: 817000 :( 😻 😈 888 eihtg DoD Fee https://medium.com/ ## Document Title :( cat- nip immed- natedly 2nd levelheading 

The result is that BeautifulSoup is able to remove over 7,000 HTML tags in a million character corpus in one second. Scaling linearly, a billion character corpus, about 200 million word, or approxiately 2000 books, would require about 200 seconds.

The rate for HTML tag removal byBeautifulSoup is about 0. 1 second per book. An acceptable rate for our production requirements.

I only benchmark BeautifulSoup. If you know of a competitive alternative method, please let me know.

Note: The compute times you get may be multiples of time longer or shorter if you are using the cloud or Spark.

7. NLP text preprocessing: Replace currency symbol

The currency symbols “[$¢£¤¥ƒ֏؋৲৳૱௹฿៛ℳ元円圆圓﷼\u20A0-\u20C0] “ are replaced with _CUR_using the textacy package:

%time textr = textacy.preprocessing.replace.replace_currency_symbols(long_s)
print('size: {:g} {}'.format(len(textr),textr[:text_l]))

output =>

CPU times: user 31.2 ms, sys: 1.67 ms, total: 32.9 ms
Wall time: 33.7 ms
size: 908200 :( 😻 😈 888 eihtg DoD Fee https://medium.com/ ## Document Title :( cat- nip immed- natedly 2nd levelheading . , # bhc@gmail.com f@z.yx can't Be a ckunk. _CUR_4 _CUR_123,456 won't seven _CUR_Shine _CUR__CUR_beighty?_CUR_

Note: The option textacy replace_<something> enables you to specify the replacement text. _CUR_ is the default substitution text for replace_currency_symbols.

You may have the currency symbol $ in your text. In this case you can use a regex:

%time text = re.sub('\$', '_DOL_', long_s)
print('size: {:g} {}'.format(len(text),text[:250]))

output =>

CPU times: user 8.06 ms, sys: 0 ns, total: 8.06 ms
Wall time: 8.25 ms
size: 1.3262e+06 :( 😻 😈 #google +1 608-444-0000 08-444-0004 608-444-00003 ext. 508 888 eihtg DoD Fee https://medium.com/ #hash ## <html><title>Document Title</title></html> :( cat- nip immed- natedly <html><h2>2nd levelheading</h2></html> . , # bhc@gmail.com f@z.yx can't Be a ckunk. _DOL_4 _DOL_123,456 won't seven _DOL_Shine _DOL__DOL_beighty?_DOL_ :

Note: All symbol $ in your text will be removed. Don’t use if you have LaTex or any text where multiple symbol $ are used.

8. NLP text preprocessing: Replace URL String

from textacy.preprocessing.replace import replace_urls
%time text = replace_urls(long_s,replace_with= '_URL_')
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 649 ms, sys: 112 µs, total: 649 ms
Wall time: 646 ms
size: 763800
:( 😻 😈 888 eihtg DoD Fee _URL_ ## Document Title :(

9. NLP text preprocessing: Remove URL String

from textacy.preprocessing.replace import replace_urls
%time text = replace_urls(long_s,replace_with= '')
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 633 ms, sys: 1.35 ms, total: 635 ms
Wall time: 630 ms
size: 744800
:( 😻 😈 888 eihtg DoD Fee ## Document Title :(

The rate for URL replace or removal is about 4,000 URLs per 1 million characters per second. Fast enough for 10 books in a corpus.

10. NLP text preprocessing: Replace E-mail string

%time text = textacy.preprocessing.replace.replace_emails(long_s)
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 406 ms, sys: 125 µs, total: 406 ms
Wall time: 402 ms
size: 725800
:( 😻 😈 888 eihtg DoD Fee ## Document Title :( cat-
nip immed-
natedly 2nd levelheading . , # _EMAIL_ _EMAIL_ can't Be a ckunk. $4 $123,456 won't seven $Shine $$beighty?$

The rate for email reference replace is about 8,000 emails per 1.7 million characters per second. Fast enough for 17 books in a corpus.

11. NLP text pre-processing: Remove E-mail string

from textacy.preprocessing.replace import replace_emails

%time text = textacy.preprocessing.replace.replace_emails(long_s,replace_with= '')
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 413 ms, sys: 1.68 ms, total: 415 ms
Wall time: 412 ms
size: 672600 :( 😻 😈 888 eihtg DoD Fee ## Document Title :( cat-
nip immed-
natedly 2nd levelheading . , # can't Be a ckunk. $4 $123,456 won't seven $Shine $$beighty?$

The rate for email reference removal is about 8,000 emails per 1.1 million characters per second. Fast enough for 11 books in a corpus.

12. NLP text preprocessing: normalize_hyphenated_words

from textacy.preprocessing.normalize import normalize_hyphenated_words
%time long_s = normalize_hyphenated_words(long_s)
print('size: {:g} {}'.format(len(long_s),long_s[:text_l])))

output =>

CPU times: user 186 ms, sys: 4.58 ms, total: 191 ms
Wall time: 190 ms
size: 642200 :
( 😻 😈 888 eihtg DoD Fee ## Document Title :( catnip immednatedly

Approximately 8,000 hyphenated-words, cat — nip and immed- iately (mispelled) were corrected in a corpus of 640,000 characters in 190 ms or abouut 3 million per second.

13. NLP text preprocessing: Convert all characters to lower case

### - **all characters to lower case;**
%time long_s = long_s.lower()
print('size: {:g} {}'.format(len(long_s),long_s[:text_l]))

output =>

CPU times: user 4.82 ms, sys: 953 µs, total: 5.77 ms
Wall time: 5.97 ms
size: 642200
:( 😻 😈 888 eihtg dod fee ## document title :( catnip immednatedly 2nd levelheading . , # can't be a ckunk. $4 $123,456 won't seven $shine $$beighty?$

I only benchmark the .lower Python function. The rate for lower case transformation by.lower() of a Python string of a million characters is about 6 ms. A rate that far exceeds our production rate requirements.

14. NLP text preprocessing: Whitespace Removal

%time text = re.sub(' +', ' ', long_s)
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 44.9 ms, sys: 2.89 ms, total: 47.8 ms
Wall time: 47.8 ms
size: 570000
:( 😻 😈 888 eihtg dod fee ## document title :( catnip immednatedly 2nd levelheading . , # can't be a ckunk. $4 $123,456 won't seven $shine $$beighty?$

The rate is about 0.1 seconds for 1 million characters.

15. NLP text preprocessing: Whitespace Removal (slower)

from textacy.preprocessing.normalize import normalize_whitespace

%time text= normalize_whitespace(long_s)
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 199 ms, sys: 3.06 ms, total: 203 ms
Wall time: 201 ms
size: 569999
:( 😻 😈 888 eihtg dod fee ## document title :( catnip immednatedly 2nd levelheading . , # can't be a ckunk. $4 $123,456 won't seven $shine $$beighty?$

normalize_whitespce is 5x slower but more general. For safety in production, we use normalize_whitespce.To date, we do not think we had any problems with faster regex.

16. NLP text preprocessing: Remove Punctuation

from textacy.preprocessing.remove import remove_punctuation

%time text = remove_punctuation(long_s, marks=',.#$?')
print('size: {:g} {}'.format(len(text),text[:text_l]))

output =>

CPU times: user 34.5 ms, sys: 4.82 ms, total: 39.3 ms
Wall time: 39.3 ms
size: 558599
:( 😻 😈 888 eihtg dod fee document title :( catnip immednatedly 2nd levelheading can't be a ckunk 4 123 456 won't seven shine beighty

spaCy

Creating the spaCy pipeline and Doc

In order to text pre-process with spaCy, we transform the text into a corpus Doc object. We can then use the sequence of word tokens objects of which a Doc object consists. Each token consists of attributes (discussed above) that we use later in this article to pre-process the corpus.

Our text pre-processing end goal (usually) is to produce tokens that feed into our NLP models.

  • spaCy reverses the stream of pre-processing text and then transforming text into tokens. spaCy creates a Doc of tokens. You then pre-process the tokens by their attributes.

The result is that parsing text into a Doc object is where the majority of computation lies. As we will see, pre-processing the sequence of tokens by their attributes is fast.

Adding emoji cleaning in the spaCy pipeline

import en_core_web_lg
nlp = en_core_web_lg.load() do = nlp.disable_pipes(["tagger", "parser"])
%time emoji = Emoji(nlp)
nlp.max_length = len(long_s) + 10
%time nlp.add_pipe(emoji, first=True)
%time long_s_doc = nlp(long_s)
print('size: {:g} {}'.format(len(long_s_doc),long_s_doc[:text_l]))

output =>

CPU times: user 303 ms, sys: 22.6 ms, total: 326 ms
Wall time: 326 ms
CPU times: user 23 µs, sys: 0 ns, total: 23 µs
Wall time: 26.7 µs
CPU times: user 7.22 s, sys: 1.89 s, total: 9.11 s
Wall time: 9.12 s
size: 129199
:( 😻 😈 888 eihtg dod fee document title :( catnip immednatedly 2nd levelheading can't be a ckunk 4 123 456 won't seven shine beighty

Creating the token sequence required at 14,000 tokens per second. We will quite a speedup when we use NVIDIA gpu.

nlp.pipe_names output => ['emoji', 'ner']

Note: The tokenizer is a “special” component and isn’t part of the regular pipeline. It also doesn’t show up in nlp.pipe_names. The reason is that there can only be one tokenizer, and while all other pipeline components take a Doc and return it, the tokenizer takes a string of text and turns it into a Doc. You can still customize the tokenizer. You can either create your own Tokenizer class from scratch, or even replace it with an entirely custom function.

spaCy Token Attributes for Doc Token Preprocessing

As we saw earlier, spaCy provides convenience methods for many other pre-processing tasks. It turns — for example, to remove stop words you can reference the .is_stop attribute.

dir(token[0]) output=> 'ancestors', 'check_flag', 'children', 'cluster', 'conjuncts', 'dep', 'dep_', 'doc', 'ent_id', 'ent_id_', 'ent_iob', 'ent_iob_', 'ent_kb_id', 'ent_kb_id_', 'ent_type', 'ent_type_', 'get_extension', 'has_extension', 'has_vector', 'head', 'i', 'idx', 'is_alpha', 'is_ancestor', 'is_ascii', 'is_bracket', 'is_currency', 'is_digit', 'is_left_punct', 'is_lower', 'is_oov', 'is_punct', 'is_quote', 'is_right_punct', 'is_sent_end', 'is_sent_start', 'is_space', 'is_stop', 'is_title', 'is_upper', 'lang', 'lang_', 'left_edge', 'lefts', 'lemma', 'lemma_', 'lex_id', 'like_email', 'like_num', 'like_url', 'lower', 'lower_', 'morph', 'n_lefts', 'n_rights', 'nbor', 'norm', 'norm_', 'orth', 'orth_', 'pos', 'pos_', 'prefix', 'prefix_', 'prob', 'rank', 'remove_extension', 'right_edge', 'rights', 'sent', 'sent_start', 'sentiment', 'set_extension', 'shape', 'shape_', 'similarity', 'string', 'subtree', 'suffix', 'suffix_', 'tag', 'tag_', 'tensor', 'text', 'text_with_ws', 'vector', 'vector_norm', 'vocab', 'whitespace_']

Attributes added by emoji and new.

dir(long_s_doc[0]._) output => ['emoji_desc', 'get', 'has', 'is_emoji', 'set', 'trf_alignment', 'trf_all_attentions', 'trf_all_hidden_states', 'trf_d_all_attentions', 'trf_d_all_hidden_states', 'trf_d_last_hidden_state', 'trf_d_pooler_output', 'trf_end', 'trf_last_hidden_state', 'trf_pooler_output', 'trf_separator', 'trf_start', 'trf_word_pieces', 'trf_word_pieces_'

I show spaCy performing preprocessing that results in a Python string corpus. The corpus is used to create a new sequence of spaCy tokens (Doc).

There is a faster way to accomplish spaCy preprocessing with spaCy pipeline extensions [2], which I show in an upcoming blog.

17. EMOJI Sentiment Score

EMOJI Sentiment Score is not a text preprocessor in the classic sense.

However, we find that emoji almost always is the dominating text in a document.

For example, two similar phrases from legal notes e-mail with opposite sentiment.

The client was challenging. :( The client was difficult. :)

We calcuate only emoji when present in a note or e-mail.

%time scl = [EMOJI_TO_SENTIMENT_VALUE[token.text] for token in long_s_doc if (token.text in EMOJI_TO_SENTIMENT_VALUE)]
len(scl), sum(scl), sum(scl)/len(scl)

output =>

CPU times: user 179 ms, sys: 0 ns, total: 179 ms
Wall time: 178 ms
(15200, 1090.7019922523152, 0.07175671001659968)

The sentiment was 0.07 (neutral) for 0.5 million character “note” with 15,200 emojis and emojicons in 178 ms. A fast sentiment analysis calculation!

18. NLP text preprocessing: Removing emoji

You can remove emoji using spaCy pipeline add-on

%time long_s_doc_no_emojicon = [token for token in long_s_doc if token._.is_emoji == False]
print('size: {:g} {}'.format(len(long_s_doc_no_emojicon),long_s_doc_no_emojicon[:int(text_l/5)]))

output =>

CPU times: user 837 ms, sys: 4.98 ms, total: 842 ms
Wall time: 841 ms
size: 121599
[:(, 888, eihtg, dod, fee, , document, title, :(, catnip, immednatedly, 2nd, levelheading, , ca, n't, be, a, ckunk, , 4, , 123, 456, wo, n't, seven, , shine, , beighty, , :(, 888, eihtg, dod, fee, , document, title, :(, catnip, immednatedly, 2nd, levelheading, , ca, n't, be, a, ckunk, , 4, , 123, 456, wo, n't, seven, , shine, , beighty, , :(, 888, eihtg, dod, fee, ]

The emoji spacy pipeline addition detected the emojicons, 😻 😈, but missed :) and :(.

19. NLP text pre-processing: Removing emoji (better)

We developed EMOJI_TO_PHRASEto detect the emojicons, 😻 😈, and emoji, such as :) and :(. and removed them [8,9].

%time text = [token.text if (token.text in EMOJI_TO_PHRASE) == False \
else '' for token in long_s_doc]
%time long_s = ' '.join(text)
print('size: {:g} {}'.format(len(long_s),long_s[:text_l]))

output =>

CPU times: user 242 ms, sys: 3.76 ms, total: 245 ms
Wall time: 245 ms
CPU times: user 3.37 ms, sys: 73 µs, total: 3.45 ms
Wall time: 3.46 ms
size: 569997
888 eihtg dod fee document title catnip immednatedly 2nd levelheading ca n't be a ckunk 4 123 456 wo n't seven shine beighty 888 eihtg dod fee document title catnip immednatedly 2nd levelheading ca n't be a ckunk 4 123 456 wo n't seven shine beighty 888 eihtg dod fee document title catnip imm

20. NLP text pre-processing: Replace emojis with a phrase

We can translate emojicon into a natural language phrase.

%time text = [token.text if token._.is_emoji == False else token._.emoji_desc for token in long_s_doc]
%time long_s = ' '.join(text)
print('size: {:g} {}'.format(len(long_s),long_s[:250]))

output =>

CPU times: user 1.07 s, sys: 7.54 ms, total: 1.07 s
Wall time: 1.07 s
CPU times: user 3.78 ms, sys: 0 ns, total: 3.78 ms
Wall time: 3.79 ms
size: 794197
:( smiling cat face with heart-eyes smiling face with horns 888 eihtg dod fee document title :( catnip immednatedly 2nd levelheading ca n't be a ckunk 4 123 456 wo n't seven shine beighty

The emoji spaCy pipeline addition detected the emojicons, 😻 😈, but missed :) and :(.

21. NLP text pre-processing: Replace emojis with a phrase (better)

We can translate emojicons into a natural language phrase.

%time text = [token.text if (token.text in EMOJI_TO_PHRASE) == False \
else EMOJI_TO_PHRASE[token.text] for token in long_s_doc]
%time long_s = ' '.join(text)
print('size: {:g} {}'.format(len(long_s),long_s[:text_l]))

output =>

CPU times: user 251 ms, sys: 5.57 ms, total: 256 ms
Wall time: 255 ms
CPU times: user 3.54 ms, sys: 91 µs, total: 3.63 ms
Wall time: 3.64 ms
size: 904397
FROWNING FACE SMILING CAT FACE WITH HEART-SHAPED EYES SMILING FACE WITH HORNS 888 eihtg dod fee document title FROWNING FACE catnip immednatedly 2nd levelheading ca n't be a ckunk 4 123 456 wo n't seven shine beighty FROWNING FAC

Again. EMOJI_TO_PHRASE detected the emojicons, 😻 😈, and emoji, such as :) and :(. and substituted a phrase.

22. NLP text preprocessing: Correct Spelling

We will use symspell for spelling correction [14].

SymSpell, based on the Symmetric Delete spelling correction algorithm, just took 0.000033 seconds (edit distance 2) and 0.000180 seconds (edit distance 3) on an old MacBook Pro [14].

%time sym_spell_setup() 
%time tk = [check_spelling(token.text) for token in long_s_doc[0:99999]]
%time long_s = ' '.join(tk)
print('size: {:g} {}'.format(len(long_s),long_s[:250]))

output =>

CPU times: user 5.22 s, sys: 132 ms, total: 5.35 s
Wall time: 5.36 s
CPU times: user 25 s, sys: 12.9 ms, total: 25 s
Wall time: 25.1 s
CPU times: user 3.37 ms, sys: 42 µs, total: 3.41 ms
Wall time: 3.42 ms
size: 528259 FROWNING FACE SMILING CAT FACE WITH HEART a SHAPED EYES SMILING FACE WITH HORNS 888 eight do fee document title FROWNING FACE catnip immediately and levelheading a not be a chunk a of 123 456 to not seven of shine of eighty

Spell correction was accomplished for immednatedly, ckunk and beight. Correcting mis-spelled words is our largest computation. It required 30 seconds for 0.8 million characters.

23. NLP text preprocessing: Replacing Currency Symbol (spaCy)

%time token = [token.text if token.is_currency == False else '_CUR_' for token in long_s_doc]
%time long_s = ' '.join(token)
print('size: {:g} {}'.format(len(long_s),long_s[:text_l]))aa

Note: spacy removes all punctuation including :) emoji and emoticon. You can protect the emoticon with:

%time long_s_doc = [token for token in long_s_doc if token.is_punct == False or token._.is_emoji == True]
print('size: {:g} {}'.format(len(long_s_doc),long_s_doc[:50]))

However, replace_currency_symbols and regex ignore context and replace any currency symbol. You may have multiple use of $ in your text and thus can not ignore context. In this case you can use spaCy.

%time tk = [token.text if token.is_currency == False else '_CUR_' for token in long_s_doc]
%time long_s = ' '.join(tk)
print('size: {:g} {}'.format(len(long_s),long_s[:250]))

output =>

CPU times: user 366 ms, sys: 13.9 ms, total: 380 ms
Wall time: 381 ms
CPU times: user 9.7 ms, sys: 0 ns, total: 9.7 ms
Wall time: 9.57 ms
size: 1.692e+06 😻 👍 🏿 < title > Document Title</title > :( < html><h2>2nd levelheading</h2></html > bhc@gmail.com f@z.y a$@ ca n't bc$$ ef$4 5 66 _CUR_ wo nt seven eihtg _CUR_ nine _CUR_ _CUR_ zer$ 😻 👍 🏿 < title > Document Title</title > :( < html><h2>2nd leve

24. NLP text preprocessing: Removing e-mail address (spacy)

%time tokens = [token for token in long_s_doc if not token.like_email]
print('size: {:g} {}'.format(len(tokens),tokens[:int(text_l/3)]))

output =>

CPU times: user 52.7 ms, sys: 3.09 ms, total: 55.8 ms
Wall time: 54.8 ms
size: 99999

About 0.06 second for 1 million characters.

25. NLP text preprocessing: Remove whitespace and punctuation (spaCy)

%time tokens = [token.text for token in long_s_doc if (token.pos_ not in ['SPACE','PUNCT'])]
%time text = ' '.join(tokens)
print('size: {:g} {}'.format(len(text),text[:text_l]))

26. NLP text preprocessing: Removing stop-words

NLP models (ex: logistic regression and transformers) and NLP tasks (Sentiment Analysis) continue to be added. Some benefit from stopword removal, and some will not. [2]

Note: We now only use different deep learning language models (transformers) and do not remove stopwords.

%time tokens = [token.text for token in long_s_doc if token.is_stop == False]
%time long_s = ' '.join(tokens)
print('size: {:g} {}'.format(len(long_s),long_s[:text_l]))

27. NLP text pre-processing: Lemmatization

Lemmatization looks beyond word reduction and considers a language’s full vocabulary to apply a morphological analysis to words.

Lemmatization looks at the surrounding text to determine a given word’s part of speech. It does not categorize phrases.

%time tokens = [token.lemma_ for token in long_s_doc]
%time long_s = ' '.join(tokens)
print('size: {:g} {}'.format(len(long_s),long_s[:text_l]))

output =>

CPU times: user 366 ms, sys: 13.9 ms, total: 380 ms
Wall time: 381 ms
CPU times: user 9.7 ms, sys: 0 ns, total: 9.7 ms
Wall time: 9.57 ms
size: 1.692e+06 😻 👍 🏿 < title > Document Title</title > :( < html><h2>2nd levelheading</h2></html > bhc@gmail.com f@z.y a$@ ca n't bc$$ ef$4 5 66 _CUR_ wo nt seven eihtg _CUR_ nine _CUR_ _CUR_ zer$ 😻 👍 🏿 < title > Document Title</title > :( < html><h2>2nd leve

Note: Spacy does not have stemming. You can add if it is you want. Stemming does not work as well as Lemmazatation because Stemming does not consider context [2] (Why some researcher considers spacy “opinionated”).

Note: If you do not know what is Stemming, you can still be on the Survivor show. (my opinion)

Conclusion

Whatever the NLP task, you need to clean (pre-process) the data (text) into a corpus (document or set of documents) before it is input into any NLP model.

I adopt a text pre-processing framework that has three major categories of NLP text pre-processing:

  1. Noise Removal
  • Transform Unicode characters into text characters.
  • convert a document image into segmented image parts and text snippets [10];
  • extract data from a database and transform into words;
  • remove markup and metadata in HTML, XML, JSON, .md, etc.;
  • remove extra whitespaces;
  • remove emoji or convert emoji into phases;
  • Remove or convert currency symbol, URLs, email addresses, phone numbers, hashtags, other identifying tokens;
  • The correct mis-spelling of words (tokens) [7];
  • Remove remaining unwanted punctuation;

2. Tokenization

  • They are splitting strings of text into smaller pieces, or “tokens.” Paragraphs segment into sentences, and sentences tokenize into words.

3. Normalization

  • Change all characters to lower case;
  • Remove English stop words, or whatever language the text is in;
  • Perform Lemmatization or Stemming.

Note: The tasks listed in Noise Removal and Normalization can move back and forth. The categorical assignment is for explanatory convenience.

Note: We do not remove stop-words anymore. We found that our current NLP models have higher F1 scores when we leave in stop-words.

Note: Stop-word removal is expensive computationally. We found the best way to achieve faster stop-word removal was not to do it.

Note: We saw no significant change in Deep Learning NLP models’ speed with or without stop-word removal.

Note: The Noise Removal and Normalization lists are not exhaustive. These are some of the tasks I have encountered.

Note: The latest NLP Deep Learning models are more accurate than older models. However, Deep Learning models can be impractically slow to train and are still too slow for prediction. We show in a follow-on article how we speed-up such models for production.

Note: Stemming algorithms drop off the end of the beginning of the word, a list of common prefixes and suffixes to create a base root word.

Note: Lemmatization uses linguistic knowledge bases to get the correct roots of words. Lemmatization performs morphological analysis of each word, which requires the overhead of creating a linguistic knowledge base for each language.

Note: Stemming is faster than lemmatization.

Note: Intuitively and in practice, lemmatization yields better results than stemming in an NLP Deep Learning model. Stemming generally reduces precision accuracy and increases recall accuracy because it injects semi-random noise when wrong.

Read more in How and Why to Implement Stemming and Lemmatization from NLTK.

Text preprocessing Action benchmarks

Our unique implementations, spaCy, and textacy are our current choice for short text preprocessing production fast to use. If you don’t mind the big gap in performance, I would recommend using it for production purposes, over NLTK’s implementation of Stanford’s NER.

In the next blogs, We see how performance changes using multi-processing, multithreading, Nvidia GPUs, and pySpark. Also, I will write about how and why our implementations, such as EMOJI_TO_PHRASEand EMOJI_TO_SENTIMENT_VALUE and or how to add emoji, emoticon, or any Unicode symbol.

References

[1] How Much Data Do We Create Every Day? The Mind-Blowing Stats Everyone Should Read.

[2] Industrial-Strength Natural Language Processing;Turbo-charge your spaCy NLP pipeline.

[3] NLTK 3.5 Documentation.

[4] Textacy: Text (Pre)-processing.

[5] Hugging Face.

[6] Language Models are Few-Shot Learners.

[7] re — Regular expression operations.

[8] Using millions of emoji occurrences to learn any-domain representations for detecting sentiment, emotion and sarcasm.

[9] How I Built Emojitracker.

[10] Classifying e-commerce products based on images and text.

[11] DART: Open-Domain Structured Data Record to Text Generation.

[12] Adv-BERT: BERT is not robust on misspellings! Generating nature adversarial samples on BERT.

[13] fast.ai .

[14] 1000x faster Spelling Correction.

This article was originally published on Medium and re-published to TOPBOTS with permission from the author. Read more technical guides by Bruce Cottman, Ph.D. on Medium.

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Microsoft BOT Framework: Building Blocks

I wrote an article last week introducing the ‘’Microsoft BOT Framework”. The highlight of the article was to educate the readers on how to…

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Photo by Tincho Franco on Unsplash

I wrote an article some weeks ago introducing the ‘’Microsoft BOT Framework”. The highlight of the article was to educate the readers on how to develop a basic chatbot. Although my workmates acknowledged the efforts but were interested in knowing more. In this article, I am going to dig in a little deeper with the various concepts involved with the Microsoft BOT framework.

I would be touching on the below-mentioned concepts in this article.

  • Channel
  • State
  • Prompt
  • Dialog
  • Waterfall
  • Connector
  • Activity
  • Turn

Channel

Channel is an application that is being used to interact with the BOT. Some of the current integrations are available with Teams, Slack, Workplace, Skype, Facebook, Telegram, Line, Webchat, etc.

Some channels are also available as an adapter. Check here for more details.

State

State in the context of the ChatBots means persisting metadata of the conversation between the BOT and the user at a certain moment. State management makes the conversation more meaningful (i.e the responses could be saved to be accessed at a later point of time.

Prompt

During a conversation between the user and the BOT, a prompt is an event when BOT asks a user any question. This question could be in the form of text, button, dropdown, etc.

Dialog

Dialogs allow forming flow in the conversation. A Dialog comprises of 2 steps.

  1. A prompt from the BOT requesting for info
  2. User Response to the BOT

If the user response is valid, BOT will send a new prompt for further information, else it will re-send the same prompt.

1. 8 Proven Ways to Use Chatbots for Marketing (with Real Examples)

2. How to Use Texthero to Prepare a Text-based Dataset for Your NLP Project

3. 5 Top Tips For Human-Centred Chatbot Design

4. Chatbot Conference Online

Waterfall

The waterfall is formed with a combination of Dialogs. It’s a sequence of dialogs which determines the complete flow of the conversation.

Let’s look at all of these concepts in a diagrammatic representation.

Connector

REST API used by BOT to communicate across multiple channels. The API allows the exchange of messages between BOT and the user on a specific channel.

Activity

As the name suggests, an activity is any communication between the user and the BOT. The connector API uses the activity object to send useful information back and forth. The most common activity type is the message. For a complete list of all Activity types, see here.

Turn

In any conversation between two parties, each party takes turns to respond to an activity (message). In the context of Microsoft BOT Framework, communication happens between user and BOT, hence a turn could be considered as the processing done by the BOT to respond to the user request.

Now that we have understood the basic concepts needed to build this sample, let’s have a look at our use case.

We would be building a ChatBot application which would enable users to Book a taxi. The conversational flow would be like:

Each box in the above diagram represents a Dialog.

Github: https://github.com/tarunbhatt9784/MFTSamples/tree/master/SuperTaxiBot

Step 1: Create a VS2017 project

I would set the name of the project as “SuperTaxiBot”.

Step 2: Install Nuget Package

Install Nuget Package Microsoft.Bot.Builder.Dialogs using VS2017.

Step 3: Create a DialogBot.cs

The class consists of bot logic which processes incoming activities from one or more channels and generates outgoing activities in response.

ActivityHandler defines various handlers for different types of activities. The activities used in this sample are:

  • OnTurnAsync: Handles any incoming activity.
  • OnMessageActivityAsync: Invoked when a message activity is received from the user. If overridden, this could potentially contain conversational logic. By default, this method does nothing.
  • OnMembersAddedAsync: Invoked when members other than this bot (like a user) are added to the conversation

Source: https://chatbotslife.com/microsoft-bot-framework-building-blocks-377be3d55dab?source=rss—-a49517e4c30b—4

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