生成从特定分布中提取的随机数

从正常（高斯）分布中抽取样本

# Generate 5 random numbers from a standard normal distribution
# (mean = 0, standard deviation = 1)
np.random.randn(5) 
# Out: array([-0.84423086,  0.70564081, -0.39878617, -0.82719653, -0.4157447 ])

# This result can also be achieved with the more general np.random.normal
np.random.normal(0, 1, 5)
# Out: array([-0.84423086,  0.70564081, -0.39878617, -0.82719653, -0.4157447 ])

# Specify the distribution's parameters
# Generate 5 random numbers drawn from a normal distribution with mean=70, std=10
np.random.normal(70, 10, 5)
# Out: array([ 72.06498837,  65.43118674,  59.40024236,  76.14957316,  84.29660766])

numpy.random 中还有其他几种发行版，例如 poisson，binomial 和 logistic

np.random.poisson(2.5, 5)  # 5 numbers, lambda=5
# Out: array([0, 2, 4, 3, 5])

np.random.binomial(4, 0.3, 5)  # 5 numbers, n=4, p=0.3
# Out: array([1, 0, 2, 1, 0])

np.random.logistic(2.3, 1.2, 5)  # 5 numbers, location=2.3, scale=1.2
# Out: array([ 1.23471936,  2.28598718, -0.81045893,  2.2474899 ,  4.15836878])