Iterated subplot

Question

Currently, I make a subplot (using matplotlib) with

import matplotlib.pyplot as plt
fig, (ax1, ax2, ax3) = plt.subplots(3, sharex=True)

I want a variable number (n) of subplots in my plot named ax1, ax2, ... axn So it should be something like

mylist = []
for num in xrange(n):
     mylist.append('ax'+str(num))
fig, (mylist) = plt.subplots(n, sharex=True)

However, this doesn't work because it just writes over "mylist" instead of using the names in the list.

Another solution would be if I didn't create the list and just used the names it creates for the axes, however, I do not know how to access these names. If I try to access the names with

mylist[0]

The console says

<matplotlib.axes._subplots.AxesSubplot object at 0x09BFAEF0>

How can I use this number to plot with a line such as

 ax1.plot(data[:,0], data[:,1]

score 1 · Answer 1 · answered Aug 17 '18 at 15:00

What you are trying to do is create variables dyncamically. You can do that by using the following piece of code:

vars()[str_name_of_your_variable] = variable_assignment

However this is highly discouraged since it does not provide an efficient way of handling a variable number of data. It is better to store the assignments in a list or a dictionary:

fig, axes = plt.subplots(n, sharex=True)

In axes you have all your axes, and you can select them by axes[n]. You can put that into a dictionary if you want.

score 0 · Accepted Answer · answered Aug 17 '18 at 14:58

When you create multiple axes:

fig, axes = plt.subplots(3)

axes will be a numpy array containing the 3 axes objects.

In order to use them to plot you can index the array to access the axes objects and plot as you would normally (ax.plot(...)):

axes[0].plot(x, y)

If you have many axes then you can also loop through these axes and plot:

for ax in axes.flatten():
    ax.plot(x, y)

Iterated subplot

2 Answers2