DataFrame随机采样

from pandas import DataFrame,Series
import pandas as pd
import numpy as np

# 使用numpy.random.permutation可实现对Series或DataFrame的列排列
df = DataFrame(np.arange(5*4).reshape(5,4))
print(df)
'''
    0   1   2   3
0   0   1   2   3
1   4   5   6   7
2   8   9  10  11
3  12  13  14  15
4  16  17  18  19
'''
sampler = np.random.permutation(5) # 随机采样
print(sampler)
'''
[3 4 1 0 2]
'''
print(df.take(sampler))
'''
    0   1   2   3
3  12  13  14  15
4  16  17  18  19
1   4   5   6   7
0   0   1   2   3
2   8   9  10  11
'''

 

import numpy as np

bag = np.array([5,7,-1,6,4])
sampler = np.random.randint(0,len(bag),size=10)
print(sampler) # [0 3 4 2 1 2 0 1 1 4]
draws = bag.take(sampler)
print(draws) #[ 5  6  4 -1  7 -1  5  7  7  4]