Jupyter notebook

Jupyter Notebook

The most visible changes to the language in Python 3 (honestly) are:

print is a command, not a statement (so you need parentheses)
1/2 returns 0.5 (floating point), not 0 (integer); to get 0, you use the operation 1//2

Jupyter notebooks are a browser-based environment for writing code, interspersing code and Markdown, and displaying figures, all contained in "cells".

Launch jupyter via the command:

jupyter notebook – launch notebook
Then navigate to http://localhost:8888 (or possibly a later port number, if you have multiple notebooks open)

Cell magics¶

Magics are prefaced by % at the beginning of a line for line magics and %% at the beginning of a cell for cell magics.

A much more exhaustive list of magics is here: Built-in cell magics.

Time operations with %timeit (for single line), %%timeit (for the whole cell). This command will run the line or cell multiple times and provide average timing.

%time sum(x**2 for x in range(10000))

* Execute bash commands with %%bash.

%%bash
ls

Visualizations in notebook¶

import matplotlib.pyplot as plt
%matplotlib notebook
%matplotlib inline