# 50+ Data Science and Machine Learning Cheat Sheets

Gear up to speed and have Data Science & Data Mining concepts and commands handy with these cheatsheets covering R, Python, Django, MySQL, SQL, Hadoop, Apache Spark and Machine learning algorithms.

There are thousands of packages and hundreds of functions out there in the Data science world! An aspiring data enthusiast need not know all. Here are the most important ones that have been brainstormed and captured in a compact few pages.

Mastering Data science involves understanding of statistics, Mathematics, Programming knowledge especially in R, Python & SQL and then deploying a combination of all these to derive insights using the business understanding & a human instinct—that drives decisions.

Here are the cheatsheets by category:

Python is a popular choice for beginners, yet still powerful enough to back some of the world’s most popular products and applications. It's design makes the programming experience feel almost as natural as writing in English. Python basics or Python Debugger cheatsheets for beginners covers important syntax to get started. Community-provided libraries such as numpy, scipy, sci-kit and pandas are highly relied on and the NumPy/SciPy/Pandas Cheat Sheet provides a quick refresher to these.

The R's ecosystem has been expanding so much that a lot of referencing is needed. The R Reference Card covers most of the R world in few pages.The Rstudio has also published a series of cheatsheets to make it easier for the R community. The data visualization with ggplot2 seems to be a favorite as it helps when you are working on creating graphs of your results.

For a data scientist basics of SQL are as important as any other language as well. Both PIG and Hive Query Language are closely associated with SQL- the original Structured Query Language. SQL cheatsheets provide a 5 minute quick guide to learning it and then you may explore Hive & MySQL!

Apache Spark is an engine for large-scale data processing. For certain applications, such as iterative machine learning, Spark can be up to 100x faster than Hadoop (using MapReduce). The essentials of Apache Spark cheatsheet explains its place in the big data ecosystem, walks through setup and creation of a basic Spark application, and explains commonly used actions and operations.

Hadoop emerged as an untraditional tool to solve what was thought to be unsolvable by providing an open source software framework for the parallel processing of massive amounts of data. Explore the Hadoop cheatsheets to find out Useful commands when using Hadoop on the command line. A combination of SQL & Hive functions is another one to check out.

We often find ourselves spending time thinking which algorithm is best? And then go back to our big books for reference! These cheat sheets gives an idea about both the nature of your data and the problem you're working to address, and then suggests an algorithm for you to try.

Django is a free and open source web application framework, written in Python. If you are new to Django, you can go over these cheatsheets and brainstorm quick concepts and dive in each one to a deeper level.

Mastering Data science involves understanding of statistics, Mathematics, Programming knowledge especially in R, Python & SQL and then deploying a combination of all these to derive insights using the business understanding & a human instinct—that drives decisions.

Here are the cheatsheets by category:

**Cheat sheets for Python:**Python is a popular choice for beginners, yet still powerful enough to back some of the world’s most popular products and applications. It's design makes the programming experience feel almost as natural as writing in English. Python basics or Python Debugger cheatsheets for beginners covers important syntax to get started. Community-provided libraries such as numpy, scipy, sci-kit and pandas are highly relied on and the NumPy/SciPy/Pandas Cheat Sheet provides a quick refresher to these.

- Python 2.7 Quick Reference Sheet
- Python Cheat Sheet by DaveChild
- Python Basics Reference sheet
- Python Debugger Cheatsheet
- NumPy / SciPy / Pandas Cheat Sheet
- Python OverAPI cheatsheet
- Python Decorators cheatsheet
- Python 2.4 Quick Reference Card
- Python 3 Cheat Sheet
- Python Language & Syntax Cheat Sheet

**Cheat sheets for R:**The R's ecosystem has been expanding so much that a lot of referencing is needed. The R Reference Card covers most of the R world in few pages.The Rstudio has also published a series of cheatsheets to make it easier for the R community. The data visualization with ggplot2 seems to be a favorite as it helps when you are working on creating graphs of your results.

- R cheat sheet (Google Drive)
- R functions for Regression Analysis
- R Reference Card
- R functions for Time series Analysis
- R Reference Card for Data Mining
- R Cheat Sheet
- Data Analysis the data.table way
- Interactive Web Apps cheatsheet by R studio
- Data Visualisation with ggplot2 cheatsheet by R studio
- Package Development with devtools cheatsheet by R studio
- Data Wrangling cheatsheet
- R markdown cheatsheet
- R Markdown Reference guide
- R Data Management cheatsheet
- R Cheatsheet for graphical parameters

**Cheat sheets for MySQL & SQL:**For a data scientist basics of SQL are as important as any other language as well. Both PIG and Hive Query Language are closely associated with SQL- the original Structured Query Language. SQL cheatsheets provide a 5 minute quick guide to learning it and then you may explore Hive & MySQL!

- MySQL Cheatsheet by Dave child
- SQL Cheat sheet
- SQL in one page
- MySQL Reference guide
- Visual SQL Joins
- SQL for dummies

**Cheat sheets for Spark:**Apache Spark is an engine for large-scale data processing. For certain applications, such as iterative machine learning, Spark can be up to 100x faster than Hadoop (using MapReduce). The essentials of Apache Spark cheatsheet explains its place in the big data ecosystem, walks through setup and creation of a basic Spark application, and explains commonly used actions and operations.

- https://dzone.com/refcardz/apache-spark
- Scala cheatsheets 1
- Scala cheatsheets 2
- Scala from DZone Reference Card
- Spark cheatsheet on github
- Scala on Spark Cheatsheet
- Essential Apache Spark cheatsheet by MapR

**Cheat sheets for Hadoop & Hive:**Hadoop emerged as an untraditional tool to solve what was thought to be unsolvable by providing an open source software framework for the parallel processing of massive amounts of data. Explore the Hadoop cheatsheets to find out Useful commands when using Hadoop on the command line. A combination of SQL & Hive functions is another one to check out.

- Hadoop for Dummies cheatsheet
- Getting Started Apache Hadoop Reference Card
- Hadoop Command Line cheatsheet
- Working with HDFS from the command line - Hadoop Cheat sheet
- Hive Function cheatsheet
- SQL to Hive cheatsheet

**Cheat sheets for Machine learning:**We often find ourselves spending time thinking which algorithm is best? And then go back to our big books for reference! These cheat sheets gives an idea about both the nature of your data and the problem you're working to address, and then suggests an algorithm for you to try.

- Choosing the right estimator Machine Learning cheatsheet
- Patterns for Predictive learning cheatsheet
- Machine learning algorithm cheat sheet for Microsoft Azure
- Machine Learning cheatsheet Github 1
- Machine Learning cheatsheet Github 2
- Machine Learning which algorithm performs best?
- Cheat sheet 10 machine learning algorithms R commands
- Patterns for Predictive Analytics

**Cheat sheets for Django :**Django is a free and open source web application framework, written in Python. If you are new to Django, you can go over these cheatsheets and brainstorm quick concepts and dive in each one to a deeper level.

- Django cheat sheet v.1
- Django cheatsheet 1
- Django cheatsheet 2
- Django cheatsheet 3
- Django cheatsheet 4
- Django Reference Cheatsheet
- Django Quick start guide & Cheatsheet
- Flask Cheatsheet

**Share more & Learn! Did we miss anything? Add your favorite Cheatsheet in the comments below!****Related:**- Guide to Data Science cheat sheets
- Top 20 R packages by popularity
- 150 Most Influential People in Big Data & Hadoop