jupytext: cell_metadata_filter: all,-hidden,-heading_collapsed formats: md:myst notebook_metadata_filter: all,-language_info,-toc,-jupytext.text_representation.jupytext_version,-jupytext.text_representation.format_version text_representation: extension: .md format_name: myst kernelspec: display_name: Python 3 language: python name: python3

Licence CC BY-NC-ND - Thierry Parmentelat

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Embedding pythontutor.com illustrations in Jupyter

this notebook is stored in text (markdown) format using jupytext, make sure to have this tool installed if you want to open it locally

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Installation

pip3 install ipythontutor

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Screeshot

As github won't render iframes embedded in a ipynb, here's a screenshot

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Basic Usage

# required to load the extension
%load_ext ipythontutor

In its simplest form, the code in the cell is handed over (as python3) to the excellent http://pythontutor.com/

%%ipythontutor
original = reference = [1, 2]
original[0] = 'boom'
print(reference)

Setting sizes

%%ipythontutor height=400 width=850
def fact(n):
    return 1 if n <= 1 else n * fact(n-1)
original = [fact(3), fact(4)]
reference = original[:]
original[0] = 'boom'
print(reference)

Scaling

If your page is smaller than what pythontutor can reasonably work with, you can specify a scaling ratio.

%%ipythontutor width=600 height=200 ratio=0.7
import copy
original = [1, [2, 3]]
reference = copy.deepcopy(original)
original[1][0] = 'boom'
print(reference)

Add a button to open pythontutor in a new tab

%%ipythontutor linkButton=true
def fact(n):
    return 1 if n <= 1 else n * fact(n-1)
original = [fact(3), fact(4)]
reference = original[:]
original[0] = 'boom'
print(reference)

Other settings

The following list shows the settings that can be tweaked on the magic line. See also this page about embedding pythontutor for more details on these settings:

from ipythontutor import Magics
for var, default in Magics.defaults.items():
    print(f"{var:>20} - defaults to - {default:<}")

Note on proto

The default is to use https to reach pythontutor, as this is expected to work in most cases. If that's not working for you, instead of setting proto=http on each magic cell, you can change this globally - like any other default btw - this way:

from ipythontutor import Magics
Magics.defaults['proto'] = 'http'

Using python2

%%ipythontutor py=2
print "Hey"
original = [1, 2]
copy = original[:]
original[0] = 'boom'

See also

Check out another pure approach, that does not rely on pythontutor, at the nbtutor project.