numpy 基本的数组统计方法

 1 # -*- coding: utf-8 -*-
 2 """
 3 Created on Fri Oct 30 15:38:35 2015
 4 
 5 @author: zenwan
 6 """
 7 
 8 import numpy as np
 9 import sys
10 reload(sys)
11 sys.setdefaultencoding(‘utf-8‘) 
12 
13 
14 ‘‘‘
15 数学与统计方法
16 -----------------------------------------
17 方法            说明
18 -----------------------------------------
19 sum            对数组的全部或者轴向数据求和
20 mean           算术平均数
21 std,var        标准差，方差
22 min,max        最大值和最小值
23 argmin,argmax  最小元素和最大元素的索引
24 cumsum         所有元素累计求和
25 cumprod        所有元素累计求积
26 ----------------------------------------
27 ‘‘‘
28 arr = np.random.randn(5, 4)  # 随机正太分布数据
29 print arr
30 print ‘数据之和‘, arr.sum()
31 print ‘行求和‘, arr.sum(0)
32 print ‘列求和s‘, arr.sum(axis=1)
33 print ‘均值：‘, arr.mean()
34 print ‘行均值：‘, arr.mean(axis=0)
35 print arr.std()
36 print arr.argmin()
37 print arr.cumsum()

 1 [[ 0.10030054 -2.23241737  1.02892048 -0.18729841]
 2  [ 1.29873072  0.24527345 -1.22146634  0.46558093]
 3  [-0.65625774 -0.87689633 -0.01059515 -1.13711452]
 4  [ 2.27650978 -0.83478579 -0.91689558 -1.13587926]
 5  [-0.9666233   0.97336183 -1.15523837 -1.33170819]]
 6 数据之和 -6.27449861582
 7 行求和 [ 2.05266    -2.72546421 -2.27527496 -3.32641945]
 8 列求和： [-1.29049475  0.78811876 -2.68086373 -0.61105085 -2.48020803]
 9 均值： -0.313724930791
10 行均值： [ 0.410532   -0.54509284 -0.45505499 -0.66528389]
11 1.07395315839
12 1
13 [ 0.10030054 -2.13211683 -1.10319634 -1.29049475  0.00823596  0.25350941
14  -0.96795693 -0.502376   -1.15863373 -2.03553006 -2.04612521 -3.18323973
15  -0.90672995 -1.74151574 -2.65841132 -3.79429058 -4.76091388 -3.78755205
16  -4.94279042 -6.27449862]