python matplotlib legend shows first entry of a list only

Question

I could not get all the legends to appear in matplotlib.

My Labels array is:

lab = ['Google', 'MSFT', 'APPL', 'EXXON', 'WMRT']

I use the below code to add the legend:

ax.legend(lab,loc="best")

Am seeing only 'Google' in top right corner. How to show all labels?

Full code:

import numpy as np
import matplotlib.pyplot as plt
from itertools import cycle, islice

menMeans = (8092, 812, 2221, 1000, 562)
N = len(menMeans)

lab = ['Google', 'MSFT', 'APPL', 'EXXON', 'WMRT']

ind = np.arange(N)  # the x locations for the groups
width = 0.35       # the width of the bars

fig, ax = plt.subplots()
my_colors = list(islice(cycle(['b', 'r', 'g', 'y', 'k']), None, N))
rects1 = ax.bar(ind, menMeans, width, color=my_colors,label=lab)

# add some
ax.set_ylabel('Count')
ax.set_title('Trending words and their counts')
ax.set_xticks(ind+width)
ax.legend(lab,loc="best")
plt.show()

Answer 1

The answer by @Ffisegydd may be more useful*, but it doesn't answer the question. Simply create separate bar charts for the legend, and you'll get the desired result:

for x,y,c,lb in zip(ind,menMeans,my_colors,lab):
    ax.bar(x, y, width, color=c,label=lb)

ax.legend()

* To see why this presentation may be harmful, consider what would happen if the viewer was colorblind (or this was printed in black and white).

Answer 2

Your problem is that you're only plotting once with a single ax.bar and as such your legend can only have one item (for that one plot). One way to get around this, for your plotting script, is to change the xticks and xticklabels as shown below.

When you create a legend you create an entry for each matplotlib.artist object that you have created through plotting. These objects could be a set of data points, or a line, or a set of bars in a bar chart. It doesn't matter if you have 5 or 10 bars in your bar chart as you've still only plotted one bar chart. This means you will end up only having one entry in your legend.

I have used ax.set_xticks(ind+width/2) to place the tick positions directly underneath your bars, I have then set these labels using your lab list with ax.set_xticklabels(lab).

import numpy as np
import matplotlib.pyplot as plt
from itertools import cycle, islice
import matplotlib.ticker as mtick

menMeans = (8092, 812, 2221, 1000, 562)
N = len(menMeans)

lab = ['Google', 'MSFT', 'APPL', 'EXXON', 'WMRT']

ind = np.arange(N)  # the x locations for the groups
width = 0.35       # the width of the bars

fig, ax = plt.subplots()

my_colors = list(islice(cycle(['b', 'r', 'g', 'y', 'k']), None, N))

rects1 = ax.bar(ind, menMeans, width, color=my_colors,label=lab)

ax.set_ylabel('Count')
ax.set_title('Trending words and their counts')

plt.xticks(rotation=90)

ax.set_xticks(ind+width/2)
ax.set_xticklabels(lab)

plt.show()