# matplotlib bar()实现百分比堆积柱状图

## 未使用numpy版本

```import matplotlib.pyplot as plt

labels = ['G1', 'G2', 'G3', 'G4', 'G5']
first = [20, 34, 30, 35, 27]
second = [25, 32, 34, 20, 25]
third = [21, 31, 37, 21, 28]
fourth = [26, 31, 35, 27, 21]
data = [first, second, third, fourth]

x = range(len(labels))
width = 0.35

# 将bottom_y元素都初始化为0
bottom_y = [0] * len(labels)
# 计算每组柱子的总和，为计算百分比做准备
sums = [sum(i) for i in zip(first, second, third, fourth)]
for i in data:
# 计算每个柱子的高度，即百分比
y = [a/b for a, b in zip(i, sums)]
plt.bar(x, y, width, bottom=bottom_y)
# 计算bottom参数的位置
bottom_y = [(a+b) for a, b in zip(y, bottom_y)]

plt.xticks(x, labels)
plt.title('Percent stacked bar ')
plt.show()
```

## 使用numpy版本

```import numpy as np
import matplotlib.pyplot as plt

labels = ['G1', 'G2', 'G3', 'G4', 'G5']
first = [20, 34, 30, 35, 27]
second = [25, 32, 34, 20, 25]
third = [21, 31, 37, 21, 28]
fourth = [26, 31, 35, 27, 21]
data = [first, second, third, fourth]

x = range(len(labels))
width = 0.35

# 将bottom_y元素都初始化为0
bottom_y = np.zeros(len(labels))
data = np.array(data)
# 按列计算计算每组柱子的总和，为计算百分比做准备
sums = np.sum(data, axis=0)
for i in data:
# 计算每个柱子的高度，即百分比
y = i / sums
plt.bar(x, y, width, bottom=bottom_y)
# 计算bottom参数的位置
bottom_y = y + bottom_y

plt.xticks(x, labels)
plt.title('Percent stacked bar ')
plt.show()
```