pandas记录

pandas的map方法使用

import pandas as pd
import numpy as np
data = pd.DataFrame(np.random.randint(0, 10, (4, 3)), columns=list('bde'), index=range(4))
print(data)
def mapfun(a):
    return str(a) + 'xxxxxxxxxxx'
result=data['d'].map(mapfun)
print(result)

d1 = DataFrame([
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
])
d1
----------
    0   1   2
0   1   2   3
1   4   5   6
2   7   8   9
d2 = DataFrame({
    'a': [1, 2, 3, 4],
    'b': [5, 6, 7, 8],
    'c': [9, 10, 11, 12],
    'd': [13, 14, 15, 16]
})
d2
----------
    a   b   c   d
0   1   5   9   13
1   2   6   10  14
2   3   7   11  15
3   4   8   12  16
d3 = DataFrame({
    'Smith': {'age': 10, 'sex': '男'},
    'Obama': {'age': 10, 'sex': '男'},
    'Trump': {'age': 10, 'sex': '男'},
})
d3
----------
    Obama   Smith   Trump
age   10      10     10
sex   男      男      男