Python data manipulation from Pandas Library

Python data manipulation from Pandas Library

The Pandas library is the most popular Python data manipulation library. It provides an easy way to manipulate data through its data-frame API, inspired from R’s data-frames.

The Pandas library is the most popular Python data manipulation library. It provides an easy way to manipulate data through its data-frame API, inspired from R’s data-frames.

Understanding The Pandas Library

One of the keys to getting a good understanding of Pandas, is to understand that Pandas is mostly a wrapper around a series of other Python Libraries. The main ones being Numpy, SQL Alchemy, Matplot lib and Openpyxl.

The core internal model of the data-frame is a series of Numpy array’s, and Pandas functions such as the now deprecated “as_matrix” return results in that internal representation.

Pandas leverages other libraries to get data in and out of data-frames, SQL Alchemy for instances is used through the read_sql and to_sql functions. And openpyxl and xlsx writer are used for read_excel and to_excel functions.

Matplotlib and Seaborn are instead used to provide an easy interface to plot information available within a data frame, using command such as df.plot()

Numpy’s Panda — Efficient pandas

One of the complain that you often hear is that Python is slow or that it is difficult to handle large amount of data. Most often than not, this is due to poor efficiency of the code being written. It is true that native Python code tends to be slower than compiled code, but libraries like Pandas effectively provides an interface in Python code to compiled code. Knowing how to properly interface with it, let us get the best out of Pandas/Python.

APPLY & VECTORIZED OPERATIONS

Pandas, like its underlying library Numpy, performs vectorized operations more efficiently than performing loops. These efficiencies are due to vectorized operations being performed through C compiled code, rather than native python code and on the ability of vectorized operations to operate on entire datasets.

The apply interface allows to gain some of the efficiency by using a CPython interfaces to do the looping:

df.apply(lambda x: x['col_a'] * x['col_b'], axis=1)

But most of the performance gain would be obtained from the use of vectorized operation themselves, be it directly in pandas or by calling its’ internal Numpy arrays directly.

As you can see from the picture above the difference in performance can be drastic, between processing it with a vectorized operation (3.53ms) and looping with apply to do an addition (27.8s). Additional efficiencies can be obtained by directly invoking the numpy’s arrays and api, eg:

***Swifter: ***swifter is a python library that makes it easy to vectorize different types of operations on dataframe, its API is fairly similar to that of the apply function

EFFICIENT DATA STORING THROUGH DTYPES

When loading a data-frame into memory, be it through read_csv, or read_excel or some other data-frame read function, SQL makes type inference which might prove to be inefficient. These api allow you to specify the types of each columns explicitly. This allows for a more efficient storage of data in memory.

df.astype({'testColumn': str, 'testCountCol': float})

Dtypes are native object from Numpy, which allows you to define the exact type and number of bits used to store certain informations.

Numpy’s dtype np.dtype('int32') would for instance represent a 32 bits long integer. Pandas default to set up integer to 64 bits, we could be save half the space when using a 32 bits:

memory_usage() shows the number of bytes used by each of the columns, since there is only one entry (row) per column, the size of each int64 column is 8bytes and of int32 4bytes.

Pandas also introduces the categorical dtype, that allows for efficient memory utilization for frequently occurring values. In the example below, we can see a 28x decrease in memory utilization for the field posting_date when we converted it to a categorical value.

In our example, the overall size of the data-frame drops by more than 3X by just changing this data type:

Not only using the right dtypes allows you to handle larger datasets in memory, it also makes some computations become more effective. In the example below, we can see that using categorical type brought a 3X speed improvement for the groupby / sum operation.

Within pandas, you can define the dtypes during the data load (read_ ) or as a type conversion (astype).

***CyberPandas: ***Cyber pandas is one of the different library extension that enables a richer variety of datatypes by supporting ipv4 and ipv6 data types and storing them efficiently.

HANDLING LARGE DATASETS WITH CHUNKS

Pandas allows for the loading of data in a data-frame by chunks, it is therefore possible to process data-frames as iterators and be able to handle data-frames larger than the available memory.

The combination of defining a chunksize when reading a data source and the get_chunk method, allows pandas to process data as an iterator. For instance, in the example shown above, the data frame is read 2 rows at the time. These chunks can then be iterated through:

i = 0
for a in df_iter:
  # do some processing  chunk = df_iter.get_chunk()
  i += 1
  new_chunk = chunk.apply(lambda x: do_something(x), axis=1)
  new_chunk.to_csv("chunk_output_%i.csv" % i )

The output of which can then be fed to a csv file, pickled, exported to a database, etc…

setting up operator by chunks also allows certain operations to be perform through multi-processing.

Dask: is a for instance, a framework built on top of Pandas and build with multi-processing and distributed processing in mind. It makes use of collections of chunks of pandas data-frames both in memory and on disk.

SQL Alchemy’s Pandas — Database Pandas

Pandas also is built up on top of SQL Alchemy to interface with databases, as such it is able to download datasets from diverse SQL type of databases as well as push records to it. Using the SQL Alchemy interface rather than the Pandas’ API directly allows us to do certain operations not natively supported within pandas such as transactions or upserts:

SQL TRANSACTIONS

Pandas can also make use of SQL transactions, handling commits and rollbacks. Pedro Capelastegui, explained in one of his blog post notably, how pandas could take advantage of transactions through a SQL alchemy context manager.

with engine.begin() as conn:
  df.to_sql(
    tableName,
    con=conn,
    ...
  )

the advantage of using a SQL transaction, is the fact that the transaction would roll back should the data load fail.

SQL extension

PandaSQL

Pandas has a few SQL extension such as pandasql a library that allows to perform SQL queries on top of data-frames. Through pandasql the data-frame object can be queried directly as if they were database tables.

SQL UPSERTs

Pandas doesn’t natively support upsert exports to SQL on databases supporting this function. Patches to pandas exists to allow this feature.

MatplotLib/Seaborn — Visual Pandas

Matplotlib and Searborn visualization are already integrated in some of the dataframe API such as through the .plot command. There is a fairly comprehensive documentation as how the interface works, on pandas’ website.

Extensions: Different extensions exists such as Bokeh and plotly to provide interactive visualization within Jupyter notebooks, while it is also possible to extend matplotlib to handle 3D graphs.

Other Extensions

Quite a few other extensions for pandas exists, which are there to handle no-core functionalities. One of them is tqdm, which provides a progress bar functionality for certain operations, another is pretty pandas which allows to format dataframes and add summary informations.

tqdm

tqdm is a progress bar extension in python that interacts with pandas, it allows user to see the progress of maps and applys operations on pandas dataframe when using the relevant function (progress_map and progress_apply):

PrettyPandas

PrettyPandas is a library that provides an easy way to format data-frames and to add table summaries to them:

Data Science vs Data Analytics vs Big Data

Data Science vs Data Analytics vs Big Data

When we talk about data processing, Data Science vs Big Data vs Data Analytics are the terms that one might think of and there has always been a confusion between them. In this article on Data science vs Big Data vs Data Analytics, I will understand the similarities and differences between them

When we talk about data processing, Data Science vs Big Data vs Data Analytics are the terms that one might think of and there has always been a confusion between them. In this article on Data science vs Big Data vs Data Analytics, I will understand the similarities and differences between them

We live in a data-driven world. In fact, the amount of digital data that exists is growing at a rapid rate, doubling every two years, and changing the way we live. Now that Hadoop and other frameworks have resolved the problem of storage, the main focus on data has shifted to processing this huge amount of data. When we talk about data processing, Data Science vs Big Data vs Data Analytics are the terms that one might think of and there has always been a confusion between them.

In this article on Data Science vs Data Analytics vs Big Data, I will be covering the following topics in order to make you understand the similarities and differences between them.
Introduction to Data Science, Big Data & Data AnalyticsWhat does Data Scientist, Big Data Professional & Data Analyst do?Skill-set required to become Data Scientist, Big Data Professional & Data AnalystWhat is a Salary Prospect?Real time Use-case## Introduction to Data Science, Big Data, & Data Analytics

Let’s begin by understanding the terms Data Science vs Big Data vs Data Analytics.

What Is Data Science?

Data Science is a blend of various tools, algorithms, and machine learning principles with the goal to discover hidden patterns from the raw data.

[Source: gfycat.com]

It also involves solving a problem in various ways to arrive at the solution and on the other hand, it involves to design and construct new processes for data modeling and production using various prototypes, algorithms, predictive models, and custom analysis.

What is Big Data?

Big Data refers to the large amounts of data which is pouring in from various data sources and has different formats. It is something that can be used to analyze the insights which can lead to better decisions and strategic business moves.

[Source: gfycat.com]

What is Data Analytics?

Data Analytics is the science of examining raw data with the purpose of drawing conclusions about that information. It is all about discovering useful information from the data to support decision-making. This process involves inspecting, cleansing, transforming & modeling data.

[Source: ibm.com]

What Does Data Scientist, Big Data Professional & Data Analyst Do?

What does a Data Scientist do?

Data Scientists perform an exploratory analysis to discover insights from the data. They also use various advanced machine learning algorithms to identify the occurrence of a particular event in the future. This involves identifying hidden patterns, unknown correlations, market trends and other useful business information.

Roles of Data Scientist

What do Big Data Professionals do?

The responsibilities of big data professional lies around dealing with huge amount of heterogeneous data, which is gathered from various sources coming in at a high velocity.

Roles of Big Data Professiona

Big data professionals describe the structure and behavior of a big data solution and how it can be delivered using big data technologies such as Hadoop, Spark, Kafka etc. based on requirements.

What does a Data Analyst do?

Data analysts translate numbers into plain English. Every business collects data, like sales figures, market research, logistics, or transportation costs. A data analyst’s job is to take that data and use it to help companies to make better business decisions.

Roles of Data Analyst

Skill-Set Required To Become Data Scientist, Big Data Professional, & Data Analyst

What Is The Salary Prospect?

The below figure shows the average salary structure of **Data Scientist, Big Data Specialist, **and Data Analyst.

A Scenario Illustrating The Use Of Data Science vs Big Data vs Data Analytics.

Now, let’s try to understand how can we garner benefits by combining all three of them together.

Let’s take an example of Netflix and see how they join forces in achieving the goal.

First, let’s understand the role of* Big Data Professional* in Netflix example.

Netflix generates a huge amount of unstructured data in forms of text, audio, video files and many more. If we try to process this dark (unstructured) data using the traditional approach, it becomes a complicated task.

Approach in Netflix

Traditional Data Processing

Hence a Big Data Professional designs and creates an environment using Big Data tools to ease the processing of Netflix Data.

Big Data approach to process Netflix data

Now, let’s see how Data Scientist Optimizes the Netflix Streaming experience.

Role of Data Scientist in Optimizing the Netflix streaming experience

1. Understanding the impact of QoE on user behavior

User behavior refers to the way how a user interacts with the Netflix service, and data scientists use the data to both understand and predict behavior. For example, how would a change to the Netflix product affect the number of hours that members watch? To improve the streaming experience, Data Scientists look at QoE metrics that are likely to have an impact on user behavior. One metric of interest is the rebuffer rate, which is a measure of how often playback is temporarily interrupted. Another metric is bitrate, that refers to the quality of the picture that is served/seen — a very low bitrate corresponds to a fuzzy picture.

2. Improving the streaming experience

How do Data Scientists use data to provide the best user experience once a member hits “play” on Netflix?

One approach is to look at the algorithms that run in real-time or near real-time once playback has started, which determine what bitrate should be served, what server to download that content from, etc.

For example, a member with a high-bandwidth connection on a home network could have very different expectations and experience compared to a member with low bandwidth on a mobile device on a cellular network.

By determining all these factors one can improve the streaming experience.

3. Optimize content caching

A set of big data problems also exists on the content delivery side.

The key idea here is to locate the content closer (in terms of network hops) to Netflix members to provide a great experience. By viewing the behavior of the members being served and the experience, one can optimize the decisions around content caching.

4. Improving content quality

Another approach to improving user experience involves looking at the quality of content, i.e. the video, audio, subtitles, closed captions, etc. that are part of the movie or show. Netflix receives content from the studios in the form of digital assets that are then encoded and quality checked before they go live on the content servers.

In addition to the internal quality checks, Data scientists also receive feedback from our members when they discover issues while viewing.

By combining member feedback with intrinsic factors related to viewing behavior, they build the models to predict whether a particular piece of content has a quality issue. Machine learning models along with natural language processing (NLP) and text mining techniques can be used to build powerful models to both improve the quality of content that goes live and also use the information provided by the Netflix users to close the loop on quality and replace content that does not meet the expectations of the users.

So this is how Data Scientist optimizes the Netflix streaming experience.

Now let’s understand how Data Analytics is used to drive the Netflix success.

Role of Data Analyst in Netflix

The above figure shows the different types of users who watch the video/play on Netflix. Each of them has their own choices and preferences.

So what does a Data Analyst do?

Data Analyst creates a user stream based on the preferences of users. For example, if user 1 and user 2 have the same preference or a choice of video, then data analyst creates a user stream for those choices. And also –
Orders the Netflix collection for each member profile in a personalized way.We know that the same genre row for each member has an entirely different selection of videos.Picks out the top personalized recommendations from the entire catalog, focusing on the titles that are top on ranking.By capturing all events and user activities on Netflix, data analyst pops out the trending video.Sorts the recently watched titles and estimates whether the member will continue to watch or rewatch or stop watching etc.
I hope you have *understood *the *differences *& *similarities *between Data Science vs Big Data vs Data Analytics.

Why is Python used so widely in big data analysis despite of it being slow?

I have noticed that Python is used a lot in big data.

People call C functions from Python, then process it further in Python, then call some other libraries, possibly again in Python that also look at gigantic data arrays.

Isn't this an extremely inefficient way of doing things? Python is much slower than C++. How can it make sense to use Python in situations when large data is processed, performance-wise?

One company asked me the question "How to bind a C-function to Python that computes a 1GB floating-point array, and then to compute a total of all numbers in Python?" They ask this question from the position when they assume that the use of Python is totally normal, and one should do such things as computing a 1GB fp array in C, then copying it into a gigantic Python list, then computing a total of numbers in Python. But this question in itself assumes that things are done extremely inefficiently, isn't it? They are just indoctrinated and think that things that they do are normal when they are far from normal.

So why is Python used so widely, as opposed to using C++, for example? Is this because many people feel that Python is much easier and C++ is too hard?

Data Science with Python explained

Data Science with Python explained

An overview of using Python for data science including Numpy, Scipy, pandas, Scikit-Learn, XGBoost, TensorFlow and Keras.

An overview of using Python for data science including Numpy, Scipy, pandas, Scikit-Learn, XGBoost, TensorFlow and Keras.

So you’ve heard of data science and you’ve heard of Python.

You want to explore both but have no idea where to start — data science is pretty complicated, after all.

Don’t worry — Python is one of the easiest programming languages to learn. And thanks to the hard work of thousands of open source contributors, you can do data science, too.

If you look at the contents of this article, you may think there’s a lot to master, but this article has been designed to gently increase the difficulty as we go along.

One article obviously can’t teach you everything you need to know about data science with python, but once you’ve followed along you’ll know exactly where to look to take the next steps in your data science journey.

Table contents:

  • Why Python?
  • Installing Python
  • Using Python for Data Science
  • Numeric computation in Python
  • Statistical analysis in Python
  • Data manipulation in Python
  • Working with databases in Python
  • Data engineering in Python
  • Big data engineering in Python
  • Further statistics in Python
  • Machine learning in Python
  • Deep learning in Python
  • Data science APIs in Python
  • Applications in Python
  • Summary
Why Python?

Python, as a language, has a lot of features that make it an excellent choice for data science projects.

It’s easy to learn, simple to install (in fact, if you use a Mac you probably already have it installed), and it has a lot of extensions that make it great for doing data science.

Just because Python is easy to learn doesn’t mean its a toy programming language — huge companies like Google use Python for their data science projects, too. They even contribute packages back to the community, so you can use the same tools in your projects!

You can use Python to do way more than just data science — you can write helpful scripts, build APIs, build websites, and much much more. Learning it for data science means you can easily pick up all these other things as well.

Things to note

There are a few important things to note about Python.

Right now, there are two versions of Python that are in common use. They are versions 2 and 3.

Most tutorials, and the rest of this article, will assume that you’re using the latest version of Python 3. It’s just good to be aware that sometimes you can come across books or articles that use Python 2.

The difference between the versions isn’t huge, but sometimes copying and pasting version 2 code when you’re running version 3 won’t work — you’ll have to do some light editing.

The second important thing to note is that Python really cares about whitespace (that’s spaces and return characters). If you put whitespace in the wrong place, your programme will very likely throw an error.

There are tools out there to help you avoid doing this, but with practice you’ll get the hang of it.

If you’ve come from programming in other languages, Python might feel like a bit of a relief: there’s no need to manage memory and the community is very supportive.

If Python is your first programming language you’ve made an excellent choice. I really hope you enjoy your time using it to build awesome things.

Installing Python

The best way to install Python for data science is to use the Anaconda distribution (you’ll notice a fair amount of snake-related words in the community).

It has everything you need to get started using Python for data science including a lot of the packages that we’ll be covering in the article.

If you click on Products -> Distribution and scroll down, you’ll see installers available for Mac, Windows and Linux.

Even if you have Python available on your Mac already, you should consider installing the Anaconda distribution as it makes installing other packages easier.

If you prefer to do things yourself, you can go to the official Python website and download an installer there.

Package Managers

Packages are pieces of Python code that aren’t a part of the language but are really helpful for doing certain tasks. We’ll be talking a lot about packages throughout this article so it’s important that we’re set up to use them.

Because the packages are just pieces of Python code, we could copy and paste the code and put it somewhere the Python interpreter (the thing that runs your code) can find it.

But that’s a hassle — it means that you’ll have to copy and paste stuff every time you start a new project or if the package gets updated.

To sidestep all of that, we’ll instead use a package manager.

If you chose to use the Anaconda distribution, congratulations — you already have a package manager installed. If you didn’t, I’d recommend installing pip.

No matter which one you choose, you’ll be able to use commands at the terminal (or command prompt) to install and update packages easily.

Using Python for Data Science

Now that you’ve got Python installed, you’re ready to start doing data science.

But how do you start?

Because Python caters to so many different requirements (web developers, data analysts, data scientists) there are lots of different ways to work with the language.

Python is an interpreted language which means that you don’t have to compile your code into an executable file, you can just pass text documents containing code to the interpreter!

Let’s take a quick look at the different ways you can interact with the Python interpreter.

In the terminal

If you open up the terminal (or command prompt) and type the word ‘python’, you’ll start a shell session. You can type any valid Python commands in there and they’d work just like you’d expect.

This can be a good way to quickly debug something but working in a terminal is difficult over the course of even a small project.

Using a text editor

If you write a series of Python commands in a text file and save it with a .py extension, you can navigate to the file using the terminal and, by typing python YOUR_FILE_NAME.py, can run the programme.

This is essentially the same as typing the commands one-by-one into the terminal, it’s just much easier to fix mistakes and change what your program does.

In an IDE

An IDE is a professional-grade piece of software that helps you manage software projects.

One of the benefits of an IDE is that you can use debugging features which tell you where you’ve made a mistake before you try to run your programme.

Some IDEs come with project templates (for specific tasks) that you can use to set your project out according to best practices.

Jupyter Notebooks

None of these ways are the best for doing data science with python — that particular honour belongs to Jupyter notebooks.

Jupyter notebooks give you the capability to run your code one ‘block’ at a time, meaning that you can see the output before you decide what to do next — that’s really crucial in data science projects where we often need to see charts before taking the next step.

If you’re using Anaconda, you’ll already have Jupyter lab installed. To start it you’ll just need to type ‘jupyter lab’ into the terminal.

If you’re using pip, you’ll have to install Jupyter lab with the command ‘python pip install jupyter’.

Numeric Computation in Python

It probably won’t surprise you to learn that data science is mostly about numbers.

The NumPy package includes lots of helpful functions for performing the kind of mathematical operations you’ll need to do data science work.

It comes installed as part of the Anaconda distribution, and installing it with pip is just as easy as installing Jupyter notebooks (‘pip install numpy’).

The most common mathematical operations we’ll need to do in data science are things like matrix multiplication, computing the dot product of vectors, changing the data types of arrays and creating the arrays in the first place!

Here’s how you can make a list into a NumPy array:

Here’s how you can do array multiplication and calculate dot products in NumPy:

And here’s how you can do matrix multiplication in NumPy:

Statistics in Python

With mathematics out of the way, we must move forward to statistics.

The Scipy package contains a module (a subsection of a package’s code) specifically for statistics.

You can import it (make its functions available in your programme) into your notebook using the command ‘from scipy import stats’.

This package contains everything you’ll need to calculate statistical measurements on your data, perform statistical tests, calculate correlations, summarise your data and investigate various probability distributions.

Here’s how to quickly access summary statistics (minimum, maximum, mean, variance, skew, and kurtosis) of an array using Scipy:

Data Manipulation with Python

Data scientists have to spend an unfortunate amount of time cleaning and wrangling data. Luckily, the Pandas package helps us do this with code rather than by hand.

The most common tasks that I use Pandas for are reading data from CSV files and databases.

It also has a powerful syntax for combining different datasets together (datasets are called DataFrames in Pandas) and performing data manipulation.

You can see the first few rows of a DataFrame using the .head method:

You can select just one column using square brackets:

And you can create new columns by combining others:

Working with Databases in Python

In order to use the pandas read_sql method, you’ll have to establish a connection to a database.

The most bulletproof method of connecting to a database is by using the SQLAlchemy package for Python.

Because SQL is a language of its own and connecting to a database depends on which database you’re using, I’ll leave you to read the documentation if you’re interested in learning more.

Data Engineering in Python

Sometimes we’d prefer to do some calculations on our data before they arrive in our projects as a Pandas DataFrame.

If you’re working with databases or scraping data from the web (and storing it somewhere), this process of moving data and transforming it is called ETL (Extract, transform, load).

You extract the data from one place, do some transformations to it (summarise the data by adding it up, finding the mean, changing data types, and so on) and then load it to a place where you can access it.

There’s a really cool tool called Airflow which is very good at helping you manage ETL workflows. Even better, it’s written in Python.

It was developed by Airbnb when they had to move incredible amounts of data around, you can find out more about it here.

Big Data Engineering in Python

Sometimes ETL processes can be really slow. If you have billions of rows of data (or if they’re a strange data type like text), you can recruit lots of different computers to work on the transformation separately and pull everything back together at the last second.

This architecture pattern is called MapReduce and it was made popular by Hadoop.

Nowadays, lots of people use Spark to do this kind of data transformation / retrieval work and there’s a Python interface to Spark called (surprise, surprise) PySpark.

Both the MapReduce architecture and Spark are very complex tools, so I’m not going to go into detail here. Just know that they exist and that if you find yourself dealing with a very slow ETL process, PySpark might help. Here’s a link to the official site.

Further Statistics in Python

We already know that we can run statistical tests, calculate descriptive statistics, p-values, and things like skew and kurtosis using the stats module from Scipy, but what else can Python do with statistics?

One particular package that I think you should know about is the lifelines package.

Using the lifelines package, you can calculate a variety of functions from a subfield of statistics called survival analysis.

Survival analysis has a lot of applications. I’ve used it to predict churn (when a customer will cancel a subscription) and when a retail store might be burglarised.

These are totally different to the applications the creators of the package imagined it would be used for (survival analysis is traditionally a medical statistics tool). But that just shows how many different ways there are to frame data science problems!

The documentation for the package is really good, check it out here.

Machine Learning in Python

Now this is a major topic — machine learning is taking the world by storm and is a crucial part of a data scientist’s work.

Simply put, machine learning is a set of techniques that allows a computer to map input data to output data. There are a few instances where this isn’t the case but they’re in the minority and it’s generally helpful to think of ML this way.

There are two really good machine learning packages for Python, let’s talk about them both.

Scikit-Learn

Most of the time you spend doing machine learning in Python will be spent using the Scikit-Learn package (sometimes abbreviated sklearn).

This package implements a whole heap of machine learning algorithms and exposes them all through a consistent syntax. This makes it really easy for data scientists to take full advantage of every algorithm.

The general framework for using Scikit-Learn goes something like this –

You split your dataset into train and test datasets:

Then you instantiate and train a model:

And then you use the metrics module to test how well your model works:

XGBoost

The second package that is commonly used for machine learning in Python is XGBoost.

Where Scikit-Learn implements a whole range of algorithms XGBoost only implements a single one — gradient boosted decision trees.

This package (and algorithm) has become very popular recently due to its success at Kaggle competitions (online data science competitions that anyone can participate in).

Training the model works in much the same way as a Scikit-Learn algorithm.

Deep Learning in Python

The machine learning algorithms available in Scikit-Learn are sufficient for nearly any problem. That being said, sometimes you need to use the most advanced thing available.

Deep neural networks have skyrocketed in popularity due to the fact that systems using them have outperformed nearly every other class of algorithm.

There’s a problem though — it’s very hard to say what a neural net is doing and why it’s making the decisions that it is. Because of this, their use in finance, medicine, the law and related professions isn’t widely endorsed.

The two major classes of neural network are convolutional neural networks (which are used to classify images and complete a host of other tasks in computer vision) and recurrent neural nets (which are used to understand and generate text).

Exploring how neural nets work is outside the scope of this article, but just know that the packages you’ll need to look for if you want to do this kind of work are TensorFlow (a Google contibution!) and Keras.

Keras is essentially a wrapper for TensorFlow that makes it easier to work with.

Data Science APIs in Python

Once you’ve trained a model, you’d like to be able to access predictions from it in other software. The way you do this is by creating an API.

An API allows your model to receive data one row at a time from an external source and return a prediction.

Because Python is a general purpose programming language that can also be used to create web services, it’s easy to use Python to serve your model via API.

If you need to build an API you should look into the pickle and Flask. Pickle allows you to save trained models on your hard-drive so that you can use them later. And Flask is the simplest way to create web services.

Web Applications in Python

Finally, if you’d like to build a full-featured web application around your data science project, you should use the Django framework.

Django is immensely popular in the web development community and was used to build the first version of Instagram and Pinterest (among many others).

Summary

And with that we’ve concluded our whirlwind tour of data science with Python.

We’ve covered everything you’d need to learn to become a full-fledged data scientist. If it still seems intimidating, you should know that nobody knows all of this stuff and that even the best of us still Google the basics from time to time.