[FIXED] Horizontally align bar plot legends in python

Issue

I have made a multi axis graph using the following code and I am unable to arrange the legend as I want. The code of my graph is as follows:

import matplotlib.pyplot as plt
import numpy as np

x = np.arange(4)

y = [5, 7, 4, 9]
z = [9, 3, 5, 6]
r = [30, 40, 45, 37]


fig,ax = plt.subplots()

abc = ax.bar(x,y,0.25 )
cde = ax.bar(x+0.25,z,0.25)

ax.legend((abc[0], cde[0]), ('y', 'z'),bbox_to_anchor=(0., 1.02, 1, .102) , borderaxespad=0.)
ax.set_xticks(x + 0.25 / 2)
ax.set_xticklabels(('A', 'B', 'C', 'D'))

ax2 = ax.twinx()
efg = ax2.plot(x+0.25/2,r,color = 'black',label = "r")
ax2.legend(bbox_to_anchor=(0.11,1.07) , borderaxespad=0.)

plt.show()

The graph it shows is like this.

The legend on the top-right side are aligned vertically but I want them to be horizontally aligned. I couldn't find any documentation on this. I want them to be as shown in the following figure.

Solution

You need to use the ncol argument, which sets the number of columns to use in the legend, e.g. ncol=2 would give you two columns.

ax.legend(..., ncol=2)

You may then look at how to place the legend using the loc argument together with the bbox_to_anchor, to find sensible parameters and make both legends align to each other:

import matplotlib.pyplot as plt
import numpy as np

x = np.arange(4)

y = [5, 7, 4, 9]
z = [9, 3, 5, 6]
r = [30, 40, 45, 37]


fig,ax = plt.subplots()

abc = ax.bar(x,y,0.25 )
cde = ax.bar(x+0.25,z,0.25)

ax.legend((abc[0], cde[0]), ('y', 'z'),loc="lower right", bbox_to_anchor=(1., 1.02) , borderaxespad=0., ncol=2)
ax.set_xticks(x + 0.25 / 2)
ax.set_xticklabels(('A', 'B', 'C', 'D'))

ax2 = ax.twinx()
efg = ax2.plot(x+0.25/2,r,color = 'black',label = "r")
ax2.legend(bbox_to_anchor=(0,1.02),loc="lower left", borderaxespad=0.)

plt.show()

Answered By - ImportanceOfBeingErnest