Matplotlib Grouped Bar graphs not working properly

Question

I was playing with grouped bar graph in matplotlib. I am trying to plot grouped bar graphs with proper width and spacing . The data consists of median salaries of javascript developers,python developers and all developers. But I am not able to group them properly.

from matplotlib import pyplot as plt
import numpy as np

ages_x = [18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
          36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55]
x_indexes = np.arange(len(ages_x))
width = 0.9

dev_y = [17784, 16500, 18012, 20628, 25206, 30252, 34368, 38496, 42000, 46752,
         49320, 53200, 56000, 62316, 64928, 67317, 68748, 73752, 77232, 78000,
         78508, 79536, 82488, 88935, 90000, 90056, 95000, 90000, 91633, 91660, 
         98150, 98964, 100000, 98988, 100000, 108923, 105000, 103117]
plt.bar(x_indexes- width, dev_y, color='#444444',width = width, label='All Devs')

py_dev_y = [20046, 17100, 20000, 24744, 30500, 37732, 41247, 45372, 48876, 
            53850, 57287, 63016, 65998, 70003, 70000, 71496, 75370, 83640, 
            84666, 84392, 78254, 85000, 87038, 91991, 100000, 94796, 97962, 
            93302, 99240, 102736, 112285, 100771, 104708, 108423, 101407, 
            112542, 122870, 120000]
plt.bar(x_indexes, py_dev_y, width = width,label='Python')

js_dev_y = [16446, 16791, 18942, 21780, 25704, 29000, 34372, 37810, 43515,
            46823, 49293, 53437, 56373, 62375, 66674, 68745, 68746, 74583, 
            79000, 78508, 79996, 80403, 83820, 88833, 91660, 87892, 96243, 
            90000, 99313, 91660, 102264, 100000, 100000, 91660, 99240, 108000,
            105000, 104000]
plt.bar(x_indexes+width, js_dev_y,width = width, label='JavaScript')
plt.legend()
plt.savefig('plot.png')
plt.xlabel('Ages')
plt.ylabel('Median Salary (USD)')
plt.title('Median Salary (USD) by Age')
plt.xkcd()

This is how my graph is currently looking

This is how I want to look it like. Don't focus on colours and all.

You're plotting on 38 different groups, which will be always difficult to grasp. Maybe create some age intervals, so your viz can be easier to understand. Maybe I'm not understanding what do you want to achieve. You want 38*3 bars? — Juan C
Use a width that is less than one third. E.g. width=0.27. Remove the xkcd style. Then you will have a useful plot and can become clear about what exactly you want to do further. — ImportanceOfBeingErnest

William Miller William Miller · Accepted Answer · 2020-01-16T04:47:51

To expand on the comment by ImportanceOfBeingErnest, here is the output from using width = 0.27 instead of width = 0.9:

Also note that this is without the plt.xkcd() - which is not really appropriate for this plot because it obfuscates the data and doesn't handle the bar offsetting correctly:

Matplotlib Grouped Bar graphs not working properly

1 Answers