Jupyter Notebook Tips

# Magics

• Manage environment variables

  %env NUM_THREADS=4
  

  1
  

• Get details

  %timeit?
  list?
  

  1
  2
  

• Measure execution time

  # Measure entire block
  %%time
  # Measure a single line
  %timeit func()
  

  1
  2
  3
  4
  

• Execute other python/notebook

  # Excute code in demo.ipynb (can be .py)
  %run ./demo.ipynb
  # Load content in demo.py to the cell
  %load ./demo.py
  

  1
  2
  3
  4
  

• Store data between notebooks

  data = 'this is the string I want to pass to different notebook'
  %store data
  del data
  
  # Read `data` in another notebook
  %store -r data # variable name must be the same
  

  1
  2
  3
  4
  5
  6
  

• Write cell code to python file

  %%writefile pythoncode.py
  import numpy
  def append_if_not_exists(arr, x):
      if x not in arr:
          arr.append(x)
          
  def some_useless_slow_function():
      arr = list()
      for i in range(10000):
          x = numpy.random.randint(0, 10000)
          append_if_not_exists(arr, x)
  

  1
  2
  3
  4
  5
  6
  7
  8
  9
  10
  11
  

• Display file content

  %pycat pythoncode.py
  

  1
  

• Profiling

  # Profile run time
  %prun func()
  
  # Profile run time by line
  # !pip install line_profiler
  %load_ext line_profiler 
  %lprun func()
  
  # Profile memory
  # !pip install memory_profiler
  %load_ext memory_profiler 
  %mprun func()
  
  # Measure the memory use of a single statement
  %memit func()
  

  1
  2
  3
  4
  5
  6
  7
  8
  9
  10
  11
  12
  13
  14
  15
  

• Debugging

  %debug # launch ipdb debugger
  %pdb   # set breakpoint (== `import ipdb; ipdb.set_trace()`)
  

  1
  2
  

• Use other kernels for the cell

  %%python2
  %%python3
  %%ruby
  %%perl
  %%bash
  %%R
  

  1
  2
  3
  4
  5
  6
  

# Tools

• Write fast code using Cython

  !pip install cython
  %load_ext Cython
  
  %%cython
  def myltiply_by_2(float x):
      return 2.0 * x
  
  myltiply_by_2(23.) # 46.0
  

  1
  2
  3
  4
  5
  6
  7
  8
  

• Install Jupyter Contrib Extensions

  pip install https://github.com/ipython-contrib/jupyter_contrib_nbextensions/tarball/master
  pip install jupyter_nbextensions_configurator
  jupyter contrib nbextension install --user
  jupyter nbextensions_configurator enable --user
  

  1
  2
  3
  4
  

• RISE: jupyter notebook presentation

  conda install -c damianavila82 rise  # recommended
  pip install RISE  # less recommended
  

  1
  2
  

• Display media

  from IPython.display import display, Image
  display(Image('demo.jpg'))
  

  1
  2
  

• Connect Github to Binder to display notebooks to others