ipython notebook

NOTE: This is the notebook from 2013, used as reference for now.



In [30]:

    
%matplotlib inline



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from numpy import sin,cos,pi,linspace
from pylab import plot

# Play with these number and ignore the rest
R = 10
r = .4
O = 12

t = linspace(-pi,pi,3000)
x = (R+r)*cos(t) - (r+O)*cos(((R+r)/r)*t)
y = (R+r)*sin(t) - (r+O)*sin(((R+r)/r)*t)
plot(x,y)









    Out[31]:





[<matplotlib.lines.Line2D at 0x1071ccc90>]

IPython Notebook is an interactive web environment for running and annotating Python code.
IPython Notebook gives output as it is generated.
Quickly experiment with code and explore data.

Starting IPython Notebook

From the command line:

ipython notebook --pylab inline

Starts a light-weight web server locally on your machine.
This command will typically connect you to a web browser displaying the notebook dashboard.
pylab bundles some scientific computing libraries together.
inline enables embedded figures in the notebook.

Notebook Cells

An IPython Notebook is a series of "cells".
The active cell has an outline around it.
Navigate to different cells with the arrow keys.
A cell can either be code, markdown, or "raw".
Create cells from the IPython Notebook menu or better yet learn the keyboard shortcuts.
Shift-Enter : run cell
Ctrl-m b : insert cell below

Hello world



In [32]:

    
print("Hello world")









    



Hello world

Exercise

Create a new note book cell here.
Write a one line program to print your name.
Execute cell

Embedding Markdown

You can embed your notebook with markdown. Markdown is a lightweight web markup language can be inserted right into the notebook. This is useful for annotating your notebook code samples.

Nice Errors



In [43]:

    
1 + foo









    



---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-43-130777adf3f0> in <module>()
----> 1 1 + foo

NameError: name 'foo' is not defined

Inline Documentation

Executing the cell will split the pane and open documentation.



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open?

Tab Completion

Type tab after o and see what happens. You should see a pop-up drop-down menu of choices.



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o

Plotting

Ipython Notebook has inline plotting capability.



In [36]:

    
# Lissajous curve
from numpy import sin,pi,linspace
from pylab import plot

delta = pi/2
t = linspace(-pi,pi,300)
x = sin(3 * t + delta)
y = sin(5 * t)
plot(x,y)









    Out[36]:





[<matplotlib.lines.Line2D at 0x107adbf50>]

Interrupts

If IPython Notebook gets jammed up, you can restart it with the Kernel -> Interrupt and Kernel -> Restart menu items.

LaTeX

The Ipython Notebook uses mathjax to render LaTeX.

$$F(k) = \int_{-\infty}^{\infty} f(x) e^{2\pi i k} dx$$

yields:

$$F(k) = \int_{-\infty}^{\infty} f(x) e^{2\pi i k} dx$$

Run Shell Commands with `!`



In [37]:

    
!ls









    



Geocoded_METAR.ipynb          ncss.ipynb
LICENSE                       netcdf-by-coordinates.ipynb
Overview.pdf                  numpy.ipynb
Overview.pptx                 pydap.ipynb
README.old.md                 radar_level2.ipynb
README.org                    reading_netCDF.ipynb
conda_binstar.ipynb           scratch.ipynb
data                          test.png
git.ipynb                     test_wind.png
images                        todo-2014.org
intro_netCDF.ipynb            todo-2014.org~
introduction.ipynb            wakari.ipynb
ipython-notebook-server.ipynb wms_sample.ipynb
ipython-notebook.ipynb        writing_netCDF.ipynb
matplotlib.ipynb

Local or Remote Images and Even Videos



In [38]:

    
from IPython.core.display import Image 
Image(url='http://python.org/images/python-logo.gif')









    Out[38]:

Take Python Code and Display it in LaTeX

SymPy is a Python library for symbolic mathematics



In [39]:

    
from sympy import *
init_printing()
x, y = symbols("x y")
Rational(3,2)*pi + exp(I*x) / (x**2 + y)









    Out[39]:





$$\frac{3 \pi}{2} + \frac{e^{i x}}{x^{2} + y}$$

Load External Codes



In [40]:

    
loadpy http://matplotlib.org/mpl_examples/pylab_examples/simple_plot.py



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from pylab import *

t = arange(0.0, 2.0, 0.01)
s = sin(2*pi*t)
plot(t, s, linewidth=1.0)

xlabel('time (s)')
ylabel('voltage (mV)')
title('About as simple as it gets, folks')
grid(True)
savefig("test.png")
show()

Note an IPython notebook when saved as a .ipynb file is simply a JSON file that you can share with colleagues via email, dropbox, etc.
There is also a neat site called nbviewer that allows you to view and share notebooks.
Note you cannot run your code at nbviewer. It is simply a rendering of a notebook.



In [42]:

    
from IPython.display import HTML
HTML('<iframe src=http://nbviewer.ipython.org width=700 height=350></iframe>')









    Out[42]:

Some interesting IPython Notebook possibilities

Typically runs on local host, but can theoretically run remotely or on the cloud (e.g. Amazon EC2) and accessed through your web browser.
Interact with IPython Notebook in the browser so available on any platform that has a web browser (e.g., tablets).
Perform "big data" analysis where your big data live (assuming you can start a notebook server where the data are located).