Question

I want to keep the width of the bars the same no matter the number of bars compared is high or low.
I am using Matplotlib stacked bar chart.
the width of the bars is relative to the number of the bars.
Here is my sample code.

How can I make the width the same no matter the number of bars I compare from 1 to 10

import numpy as np
import matplotlib.pyplot as plt




N =1  
ind = np.arange(N)    # the x locations for the groups
width = 0.35       # the width of the bars: can also be len(x) sequence




design = []
arch = []
code = []

fig = plt.figure()



b   = [70]
a= np.array([73])
c = [66]




p1 = plt.bar(ind, a,width, color='#263F6A')
p2 = plt.bar(ind, b, width, color='#3F9AC9', bottom=a)
p3 = plt.bar(ind, c, width, color='#76787A', bottom=a+b)


plt.ylabel('Scores')
plt.title('CQI Index')


plt.xticks(ind+width/2., ('P1'))#dynamic - fed

plt.yticks(np.arange(0,300,15))


plt.legend( (p1[0], p2[0], p3[0]), ('A','B','C') )
plt.grid(True)

plt.show()

Thank you

Answer 1

The width of the bars doesn’t change, the scale of your image changes. If you want the scale to stay the same you have to manually specify what range you want to show, whether your plot is 10×10, 100×100, or 1,000,000,000 x 10

Edit:

If I understand correctly, what you want is something like this:

Graph 1 – 2 bars:

10
+---------------------------+
|                           |
|                           |
|                           |
|                           |
|                           |
|       4_                  |
|       | |                 |
|  2_   | |                 |
|  | |  | |                 |
|  | |  | |                 |
+---------------------------+ 10

Graph 2 – add 2 more bars

10
+---------------------------+
|                           |
|                           |
|                 7_        |
|                 | |       |
|                 | |       |
|       4_        | |       |
|       | |  3_   | |       |
|  2_   | |  | |  | |       |
|  | |  | |  | |  | |       |
|  | |  | |  | |  | |       |
+---------------------------+ 10

Where the apparent width of the bars hasn’t changed from Graph 1 to Graph 2. If this is what you want to do then you’ll need to set the scale of your plot

You can do that with

import matplotlib
matplotlib.use('GTKAgg')

import matplotlib.pyplot as plt
import gobject

fig = plt.figure()
ax = fig.add_subplot(111)

def draw1():
    plt.bar(0,2)
    plt.bar(2,4)
    ax.set_xlim((0,10))
    ax.set_ylim((0,10))
    fig.canvas.draw()
    return False

def draw2():
    plt.bar(4,3)
    plt.bar(6,7)

    ax.set_xlim((0,10))
    ax.set_ylim((0,10))
    fig.canvas.draw()
    return False

draw1()
gobject.timeout_add(1000, draw2)
plt.show()