Useful IPython magic commands

In this article, we will cover IPython Magic commands/functions and discuss various types of magic commands available. In this article we will be using Jupyter Notebook to execute the magic commands first, we look at what are Magic functions and why we use them, then different types of magic functions followed by examples. There are a lot of magic functions but in this article, we discuss the most commonly used magic functions.

Jupyter Notebook

The Jupyter Notebook is the original web application for creating and sharing computational documents that contain live code, equations, visualizations, and narrative text. It offers a simple, streamlined, document-centric experience. Jupyter has support for over 40 different programming languages and Python is one of them.

Magic Commands

Magic commands generally known as magic functions are special commands in IPython that provide special functionalities to users like modifying the behavior of a code cell explicitly, simplifying common tasks like timing code execution, profiling, etc. Magic commands have the prefix ‘%’ or ‘%%’ followed by the command name. There are two types of magic commands:

1. Line Magic Commands
2. Cell Magic Commands

Line Magic Commands

Line magic commands are used to provide a special functionality to a single line of code, line magic commands begin with ‘%’ followed by the line command. To check the available magic commands run ‘%lsmagic’ this command will show all the magic commands, as of now there are 97 line magic commands which are as follows:

%alias, %alias_magic, %autoawait, %autocall, %automagic, %autosave, %bookmark, %cat, %cd, %clear, %colors, %conda, %config, %connect_info, %cp, %debug, %dhist, %dirs, %doctest_mode, %ed, %edit, %env, %gui, %hist, %history, %killbgscripts, %ldir, %less, %lf, %lk, %ll, %load, %load_ext, %loadpy, %logoff, %logon, %logstart, %logstate, %logstop, %ls, %lsmagic, %lx, %macro, %magic, %man, %matplotlib, %mkdir, %more, %mv, %notebook, %page, %pastebin, %pdb, %pdef, %pdoc, %pfile, %pinfo, %pinfo2, %pip, %popd, %pprint, %precision, %prun, %psearch, %psource, %pushd, %pwd, %pycat, %pylab, %qtconsole, %quickref, %recall, %rehashx, %reload_ext, %rep, %rerun, %reset, %reset_selective, %rm, %rmdir, %run, %save, %sc, %set_env, %store, %sx, %system, %tb, %time, %timeit, %unalias, %unload_ext, %who, %who_ls, %whos, %xdel, %xmode

Since it is not possible to cover all the 97 line magic commands we will only cover the most widely and helpful commands in this article, we will look some line magic commands along with the short description followed by example of some line magic commands:

Line Magic Command	Description
%alias	Define an alias for a system command.
%alias_magic	Create an alias for an existing line or cell magic
%automagic	Make magic functions callable without having to type the initial %
%cd	Change the current working directory
%debug	Activate the interactive debugger
%dhist	Print your history of visited directories
%dirs	Return the current directory stack
%env	Get, set, or list environment variables.
%gui	Enable or disable IPython GUI event loop integration
%load	Load code into the current frontend
%load_ext	Load an IPython extension by its module name
%lsmagic	List All Available Magic Commands
%macro	Define a macro for future re-execution. It accepts ranges of history, filenames or string objects
%magic	Print Information About Magic Commands System
%matplotlib	Set up matplotlib to work interactively.
%notebook	Export and convert IPython notebooks
%pfile	Print (or run through pager) the file where an object is defined
%pip	Run the pip package manager within the current kernel
%prun	Run a statement through the python code profiler
%pwd	Return the current working directory path
%reload_ext	Reload an IPython extension by its module name
%reset	Resets the namespace by removing all names defined by the user
%run	Run the named file inside IPython as a program
%save	Save a set of lines or a macro to a given filename
%set_env	Set environment variables
%system	Shell execute – run shell command and capture output
%time	Measures time execution of a Python statement or expression
%timeit	Measures Execution Time of Line
%unalias	Remove an alias
%who	print all interactive variables, with some minimal formatting
%who_ls	Return a sorted list of all interactive variables
%whos	Like %who, but gives some extra information about each variable
%xdel	Delete a variable, trying to clear it from anywhere that IPython’s machinery has references to it.
%xmode	Switch modes for the exception handlers

Example of Line Magic Functions

1. %load

• Load the code from external file and insert in into the cell
• Syntax:

%load file_name.py

Example:

Python3

%load fibo.py

2. %run

• Run the named file inside IPython as a program
• Syntax:

%run file_name.py

Example:

Python3

%run tricks.py

Output:

3. %time

• Measure the execution time of a single Python statement or expression
• Syntax:

%time some_funtion()

Example:

Python3

def fibonacci(n):
     if n == 0 or n == 1: return n
     return fibonacci(n-1)+fibonacci(n-2)
%time fibonacci(10)

Output:

CPU times: total: user 20 ns, sys:4 ns, total: 24 ns
Wall time: 26.2 ns
55

4. %timeit

• Measure the execution time of a single Python statement or expression by performing executions multiple time to get more accurate results.
• Syntax:

%timeit some_function()

Example:

Python3

def fibonacci(n):
     if n == 0 or n == 1: return n
     return fibonacci(n-1)+fibonacci(n-2)
%timeit fibonacci(10)

Output:

14.7 µs ± 869 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)

5. %cd

• Change the current working directory
• Syntax:

%cd directory/sub_dir

Example:

Python3

%cd Form_data_visualization

Output:

Cell Magic Commands

Cell Magic functions are special commands that allow the user to modify the behavior of a code cell explicitly. Cell Magic functions have the prefix ‘%%’ followed by the command name. Cell magic functions serve various tasks and customizations which we discuss thoroughly further in this article. As per the official python documentation there are 16 cell magic functions available now which are described below,

Cell Magic Command	Description
%%bash	Run cells with bash in a subprocess
%%capture	run the cell, capturing stdout, stderr, and IPython’s rich display() calls
%%html	Render the cell as a block of HTML
%%javascript or %%js	Run the cell block of Javascript code
%%latex	Render the cell as a block of LaTeX
%%markdown	Render the cell as Markdown text block
%%perl	Run cells with perl in a subprocess
%%pypy	Run cells with pypy in a subprocess
%%python	Run cells with python in a subprocess
%%python2	Run cells with python2 in a subprocess
%%python3	Run cells with python3 in a subprocess
%%ruby	Run cells with ruby in a subprocess
%%script	Run a cell via a shell command
%%sh	Run cells with sh in a subprocess
%%svg	Render the cell as an SVG literal
%%writefile	Write the contents of the cell to a file

Since, its not possible to explain each cell magic command with example we will only cover some helpful and widely used cell magic commands.

Example of Cell Magic Functions

1. %%bash

Allows user to run Bash shell commands within the cell.

Example:

Python3

%%bash
ls -l

Output Screenshot:

2. %%html

This cell magic function renders contents of code cell as html script

Example:

Python3

%%html
<font size=10 color='hotpink'>Hello World</font>

Output Screenshot:

3. %%javascript or %%js

Allows you to execute JavaScript code within the cell

Example:

Python3

%%javascript
alert("This is a JavaScript alert!")

Output Screenshot:

4. %%latex

Renders LaTeX equations and expressions in the cell.

Python3

%%latex
$e^{i\pi} + 1 = 0$

Output Screenshot:

5. %%markdown or %%md

Renders the content of the cell as Markdown

Example:

Python3

%%markdown
# This is a Markdown Heading
* This is a bullet point

Output Screenshot: