plt.bar - > TypeError:无法连接'str'和'float'对象

Question

我有一个x_axis表示numpy数组的变量:

array(['administrator', 'retired', 'lawyer', 'none', 'student',
       'technician', 'programmer', 'salesman', 'homemaker', 'executive',
       'doctor', 'entertainment', 'marketing', 'writer', 'scientist',
       'educator', 'healthcare', 'librarian', 'artist', 'other', 'engineer'], 
      dtype='|S13')

......我的y_axis样子如下:

array([ 79,  14,  12,   9, 196,  27,  66,  12,   7,  32,   7,  18,  26,
        45,  31,  95,  16,  51,  28, 105,  67])

当我试图绘制它们时:

import matplotlib.pyplot as plt
plt.bar(x_axis,y_axis)

我收到错误:

TypeError: cannot concatenate 'str' and 'float' objects

---

注意:

我看过'类似'的问题,但没有特别询问matplotlib.bar中的这个错误.

Answer 1

那是因为bar需要x坐标,但你x_axis是一个字符串数组.所以,bar不知道在哪里画吧.您需要的是以下内容:

import numpy as np 
import matplotlib.pyplot as plt

y_axis = np.array([ 79,  14,  12,   9, 196,  27,  66,  12,   7,  32,   7,  18,  26,
        45,  31,  95,  16,  51,  28, 105,  67])

x_labels = np.array(['administrator', 'retired', 'lawyer', 'none', 'student',
       'technician', 'programmer', 'salesman', 'homemaker', 'executive',
       'doctor', 'entertainment', 'marketing', 'writer', 'scientist',
       'educator', 'healthcare', 'librarian', 'artist', 'other', 'engineer'], 
      dtype='|S13')

w = 3
nitems = len(y_axis)
x_axis = np.arange(0, nitems*w, w)    # set up a array of x-coordinates

fig, ax = plt.subplots(1)
ax.bar(x_axis, y_axis, width=w, align='center')
ax.set_xticks(x_axis);
ax.set_xticklabels(x_labels, rotation=90);
plt.show()