SciPy: Using GridSpec to Display Box Plots Under Histograms

Here's how to get output like this using matplotlib and its GridSpec class:

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.gridspec as gs

%matplotlib inline

df = pd.DataFrame([
        np.random.randn(1000),
        np.random.random_integers(1, 2, 1000)
    ]).T
df.columns = ["value", "group"]


fig = plt.figure(figsize=(10, 6))
grid = gs.GridSpec(2, 2, height_ratios=[3, 1]) 
for i, g in enumerate([1, 2]):
    
    subset = df['value'][df['group'] == g]
    
    # Histogram
    ax = plt.subplot(grid[i])
    ax.hist(list(subset), color='k', alpha=0.4)
    ax.set_title("Group %s" % g)
    
    # Box plot
    ax2 = plt.subplot(grid[i+2])
    pd.DataFrame(subset).boxplot(vert=False, return_type='axes')
    ax2.set_yticklabels([''])

fig.tight_layout()
fig.subplots_adjust(top=0.85)
fig.suptitle('Example', fontsize=20)

None # Don't display the last thing -- `%matplotlib inline` will display the graphs no matter what.


It looks like Gist embed is broken here on PostHaven for IPython notebooks, so the embed below may look strange:

Installing Python 3 Alongside Python 2 on OS X (Yosemite)

This was actually pretty easy. Here’s what I did:

  1. Opened a new Terminal window that wasn’t in a virtualenv.
  2. Ran brew update
  3. Ran brew install python3
  4. cd ~/.virtualenvs (the folder where my virtualenvs are)
  5. virtualenv -p `which python3` data3 to create a new virtualenv using Python 3
  6. workon data3 (this is from virtualenvwrapper)
  7. pip install "ipython[all]"

Update: I've been trying out pyenv, which is forked from my much-beloved rbenv. It seems to work fine with virtualenv via pyenv-virtualenv, but I could not get pyenv-virtualenvwrapper to work. I'm using this now to run an updated version of Python 2 without messing with my system Python, and it seems to work fine.

Hide Code When Sharing IPython Notebooks

When sharing IPython notebooks with non-programmers, I don't want to cause confusion by including a bunch of code.

To this end, I wrote a snippet of Python and JavaScript that can be put in a code cell at the top of a notebook. When a notebook with this code is exported as HTML or viewed with nbviewer.ipython.org, code blocks will be hidden by default. A "Toggle code" button is also added in case you want to see the hidden code.

Here is the code snippet to put in the cell at the top of the notebook:

And here is an example of how this works in nbviewer.ipython.org.

(The source code for this example and the accompanying HTML output are available here.)