A quick tour of Jupyter (aka IPython) Notebook

You can start this Jupyter (aka IPython) notebook from a terminal by running

jupyter notebook --pylab inline

The --pylab inline is for plotting graphs

First, we need to explain how to run cells. Try to run the cell below!



In [ ]:

    
import pandas as pd

print "Hi! This is a cell. Press the ▶ button above to run it"

You can also run a cell with Ctrl+Enter or Shift+Enter. Experiment a bit with that.

One of the most useful things about Jupyter notebook is its tab completion.

Try this: click just after read_csv( in the cell below and press tab, slowly



In [ ]:

    
pd.read_csv(

This is pretty useful, right?.

Okay, let's try tab completion for function names!



In [ ]:

    
pd.r

You should see this:

Shell access

Jupyter (IPython) has many cool commands, including its magic commands. For example, starting a line with ! gives you complete system shell access. This means that the IPython magic command ! ls will display the contents of your current directory. Your task is to use the IPython magic command ! ls to check out the contents of your current directory and answer the following question: which of the following files is in your working directory?



In [3]:

    
!pwd









    



/Users/pmui/datascience2016fall/lecture01.intro



In [1]:

    
!ls









    



data                    lecture01.intro.ipynb   lecture01.jupyter.ipynb
images                  lecture01.intro.pdf     tweetering.py



In [2]:

    
!open lecture01.intro.pdf

Writing code

Writing code in the notebook is pretty normal.



In [3]:

    
def print_10_nums():
    for i in range(10):
        print i,



In [4]:

    
print_10_nums()









    



0 1 2 3 4 5 6 7 8 9

Magic functions

Jupyter (aka IPython) has all kinds of magic functions. Here's an example of comparing sum() with a list comprehension to a generator comprehension using the %time magic.



In [12]:

    
%time sum([x for x in range(100000)])









    



CPU times: user 15.7 ms, sys: 2.76 ms, total: 18.4 ms
Wall time: 17.9 ms






    Out[12]:





4999950000



In [13]:

    
%time sum(x for x in xrange(100000))









    



CPU times: user 9.45 ms, sys: 2.2 ms, total: 11.6 ms
Wall time: 11.8 ms






    Out[13]:





4999950000

The magics I use most are %time and %prun for profiling. You can run %magic to get a list of all of them, and %quickref for a reference sheet.



In [14]:

    
%quickref

You can also do nutty things like run Perl code in the notebook with cell magics. This is especially cool for things like Cython code, where you can try out Cython really fast with the %%cython magic (you'll need to install it).



In [15]:

    
%%perl

$_ = "whoa, python!";
s/python/perl/;
print









    



whoa, perl!

That's it for now!