rand、randn、randi区别及用法

①random() 方法返回随机生成的一个实数，它在[0,1)范围内，不接受参数：

import random
print(random.random())#random 0.03563083745692497

②rand()方法随机样本位于[0, 1)中；参数（行，列）

import numpy as np
print("rand",np.random.rand(2,3))#rand [[0.25755196 0.81740437 0.79738575] [0.02873379 0.22991188 0.49516755]]

③randn从标准正态分布中返回一个或多个样本值；参数（行，列）

import numpy as np
print("randn",np.random.randn(2,3))#randn [[ 0.43310204  0.71676044  1.79460972][ 0.74348343 -0.52125996  1.07966401]]

④randint生成在半开半闭区间[low,high)上离散均匀分布的整数值;若high=None，则取值区间变为[0,low)；size（行，列）

import numpy as np
import random
print("randit",np.random.randint(2,3,size=(1,2)))
print("randit2",random.randint(2,3))#randit [[2 2]]
#randit2 3

⑤np.random.seed())#使每次随机生成数一样,同numpy.random.RandomState()

import numpy as np
np.random.seed(2)#使每次随机生成数一样,同numpy.random.RandomState()
print("rand1",np.random.rand(2,3))
np.random.seed(2)
print("rand2",np.random.rand(2,3))
np.random.seed(6)#使每次随机生成数一样,同numpy.random.RandomState()
print("rand3",np.random.rand(2,3))

#rand1 [[0.4359949 0.02592623 0.54966248]
[0.43532239 0.4203678 0.33033482]]
rand2 [[0.4359949 0.02592623 0.54966248]
[0.43532239 0.4203678 0.33033482]]
rand3 [[0.89286015 0.33197981 0.82122912]
[0.04169663 0.10765668 0.59505206]]