Python Jupyter Notebook: Put two histogram subplots side by side in one figure

Question

I am using Python (3.4) Jupyter Notebook. I have the following two histograms in two separated cells, each has their own figure:

bins = np.linspace(0, 1, 40)
plt.hist(list1, bins, alpha = 0.5, color = 'r')

and

bins = np.linspace(0, 1, 40)
plt.hist(list2, bins, alpha = 0.5, color = 'g')

Is it possible to put the above two histograms as two subplots side by side in one figure?

Solution 1

Yes this is possible. See the following code.

%matplotlib inline
import matplotlib.pyplot as plt
import numpy as np

list1 = np.random.rand(10)*2.1
list2 = np.random.rand(10)*3.
bins = np.linspace(0, 1, 3)

fig, ax = plt.subplots(1,2)
ax[0].hist(list1, bins, alpha = 0.5, color = 'r')
ax[1].hist(list2, bins, alpha = 0.5, color = 'g')
plt.show()

Solution 2

You can use matplotlib.pyplot.subplot for that:

import matplotlib.pyplot as plt
import numpy as np

list1 = np.random.rand(10)*2.1
list2 = np.random.rand(10)*3.0

plt.subplot(1, 2, 1)  # 1 line, 2 rows, index nr 1 (first position in the subplot)
plt.hist(list1)
plt.subplot(1, 2, 2)  # 1 line, 2 rows, index nr 2 (second position in the subplot)
plt.hist(list2)
plt.show()

Comments

[mgilson]

It's better practice to explain what you're doing. For example, the arguments of plt.subplot aren't intuitive to the un-initiated and it is frequently nice to include your imports as well :-)

[Tanmoy]

This is a solution to the question put by @Edamame to display two histograms as two subplots side by side in one figure.

[Tanmoy]

@mgilson - Edamame was already using plt.hist. So, it was inherent that s/he had already imported matplotlib.pyplot as plt. Hencce the import was not included.

[mgilson]

@Tanmoy -- Just because the asker and you know doesn't mean that future visitors to this question will know. Remember, you're not just addressing Edamame's question -- You're also addressing the questions of future visitors who might be trying to accomplish the same thing.

[fraxture]

Can you explain what you are doing with the expression for bins: np.linspace(0, 1, 3)?

[ImportanceOfBeingErnest]

@fraxture bins is the array that contains the edges of the bins for the histogram.

[WoJ]

@mgilson: I updated the answer with working code (a bit taken from the other answer).This answer helped me so it could be useful for others too, as you mention.