Stacked Bar Chart is not working properly using matplotlib

Question

I am trying to plot 100% stacked bar chart but i am getting wrong output. The aligned and the percentages are all messed up.

x = ["A","B","C","D"]
data1 = {'Price':[12,44,23,21]}
data2 = {'Cost':[15,40,10,15]}
data3 = {'Units':[22,12,23,15]}
y1 = pd.DataFrame(data1)
y2 = pd.DataFrame(data2)
y3 = pd.DataFrame(data3)
snum = y1['Price']+y2['Cost']+y3['Units']

y11 = y1['Price']/snum*100
y22 = y2['Cost']/snum*100
y33 = y3['Units']/snum*100

plt.figure(figsize=(4,3))

# stack bars
plt.bar(x, y11, label='y1')
plt.bar(x, y22 ,bottom=y11 ,label='y2')
plt.bar(x, y33 ,bottom=y11+y22+y33,label='y3')

for xpos, ypos, yval in zip(x, y11/2, y11):
    plt.text(xpos, ypos, "%.1f"%yval, ha="center", va="center")
for xpos, ypos, yval in zip(x, y11+y22/2, y22):
    plt.text(xpos, ypos, "%.1f"%yval, ha="center", va="center")
for xpos, ypos, yval in zip(x, y11+y22+y33/2, y33):
    plt.text(xpos, ypos, "%.1f"%yval, ha="center", va="center")

Maybe replace plt.bar(x, y33,bottom=y11+y22+y33,label='y3') by plt.bar(x, y33,bottom=y11+y22,label='y3') ? — JohanC
– JohanC, Commented Nov 20, 2019 at 8:25

JohanC · Accepted Answer · 2019-11-22 16:24:04Z

1

By bottom=y11+y22+y33, the third bar will start at 100% and stick out. Just remove the +y33 to get the desired result.

Here is the adapted code, also with slightly different colors. If you give the edge the same color as the bar, you avoid some possible white line between them.(I also imported the libraries and added show().)

import pandas as pd
from matplotlib import pyplot as plt

x = ["A","B","C","D"]
data1 = {'Price':[12,44,23,21]}
data2 = {'Cost':[15,40,10,15]}
data3 = {'Units':[22,12,23,15]}
y1 = pd.DataFrame(data1)
y2 = pd.DataFrame(data2)
y3 = pd.DataFrame(data3)
snum = y1['Price']+y2['Cost']+y3['Units']

y11 = y1['Price']/snum*100
y22 = y2['Cost']/snum*100
y33 = y3['Units']/snum*100

plt.figure(figsize=(4,3))

# stack bars
plt.bar(x, y11, label='y1', color='#fbb4ae', edgecolor='#fbb4ae')
plt.bar(x, y22, bottom=y11, label='y2', color='#b3cde3', edgecolor='#b3cde3')
plt.bar(x, y33, bottom=y11+y22, label='y3', color='#ccebc5', edgecolor='#ccebc5')

for xpos, ypos, yval in zip(x, y11/2, y11):
    plt.text(xpos, ypos, "%.1f"%yval, ha="center", va="center")
for xpos, ypos, yval in zip(x, y11+y22/2, y22):
    plt.text(xpos, ypos, "%.1f"%yval, ha="center", va="center")
for xpos, ypos, yval in zip(x, y11+y22+y33/2, y33):
    plt.text(xpos, ypos, "%.1f"%yval, ha="center", va="center")

plt.show()

edited Nov 22, 2019 at 16:24

answered Nov 20, 2019 at 11:52

JohanC

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1 Comment

JohanC Over a year ago

Edit: setting edgecolor to prevent white lines between bars.

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