利用pandas和numpy计算表中每一列的均值

Posted 2021-01-16 carlber

import numpy as np
import pandas as pd

df = pd.DataFrame({‘var1‘:np.random.rand(100),          #生成100个0到1之间的随机数
                   ‘var2‘:100,
                   ‘var3‘:np.random.choice([20,30,90])     #在这几个数之间选择
                   }
                  )
for col in df.columns:
    print("该列数据的均值位%.2f"  %df[col].mean())    #计算每列均值

print(df[‘var1‘])  #单独输出第一列

输出结果：

该列数据的均值位0.51
该列数据的均值位100.00
该列数据的均值位30.00

0 0.319224
1 0.529424
2 0.435089
3 0.545284
4 0.432007
5 0.652700
6 0.677978
7 0.078914
8 0.780381
9 0.426605
10 0.108600
11 0.873254
12 0.574560
13 0.750802
14 0.080483
15 0.918442
16 0.468576
17 0.714712
18 0.024530
19 0.450139
20 0.501999
21 0.915478
22 0.892921
23 0.964524
24 0.575245
25 0.812126
26 0.182105
27 0.676373
28 0.681854
29 0.348056
...
70 0.267853
71 0.726693
72 0.904409
73 0.376035
74 0.156566
75 0.827273
76 0.019732
77 0.912440
78 0.172291
79 0.514597
80 0.899262
81 0.875527
82 0.374511
83 0.837525
84 0.530692
85 0.688554
86 0.168771
87 0.141499
88 0.043769
89 0.295341
90 0.225016
91 0.371209
92 0.341240
93 0.895325
94 0.722982
95 0.588161
96 0.631062
97 0.395368
98 0.936556
99 0.069726
Name: var1, dtype: float64