Using Cython in a Jupyter notebook

Cython can be used conveniently and interactively from a web browser through the Jupyter notebook.

To enable support for Cython compilation, install Cython and load the Cython extenstion from within Jupyter.


In [1]:
%load_ext Cython


/Users/toddleonhardt/anaconda/lib/python3.5/site-packages/Cython/Distutils/old_build_ext.py:30: UserWarning: Cython.Distutils.old_build_ext does not properly handle dependencies and is deprecated.
  "Cython.Distutils.old_build_ext does not properly handle dependencies "

Then prefix a cell with the %%cython marker to compile it:


In [2]:
%%cython

cdef int a = 0
for i in range(10):
    a += i
print(a)


45

You can show Cython's code analysis by passing the --annotate option:


In [3]:
%%cython -a

def intsum(values):
    cdef int value, sum = 0
    for value in values:
        sum += value
    return sum

print(intsum(range(5)))


10
Out[3]:
Cython: _cython_magic_e9760b679edf693c36dd287fdd6e42ba.pyx

Generated by Cython 0.25.1

Yellow lines hint at Python interaction.
Click on a line that starts with a "+" to see the C code that Cython generated for it.

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In [ ]: