import numpy as np
import pandas as pd
from pandas import Series, DataFrame
创建测试的DataFrame
df1 = DataFrame(np.arange(9).reshape(3,3), index=['BJ','SH','GZ'], columns=['A','B','C'])
df1
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A |
B |
C |
BJ |
0 |
1 |
2 |
SH |
3 |
4 |
5 |
GZ |
6 |
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8 |
df1.index
Index(['BJ', 'SH', 'GZ'], dtype='object')
df1.index = Series(['bj','sh','gz'])
df1
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B |
C |
bj |
0 |
1 |
2 |
sh |
3 |
4 |
5 |
gz |
6 |
7 |
8 |
df1.index = df1.index.map(str.upper)
df1
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B |
C |
BJ |
0 |
1 |
2 |
SH |
3 |
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GZ |
6 |
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df1.rename(index=str.lower, columns=str.lower)
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b |
c |
bj |
0 |
1 |
2 |
sh |
3 |
4 |
5 |
gz |
6 |
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df1
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B |
C |
BJ |
0 |
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SH |
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GZ |
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df1.rename(index={'BJ':'beijing'},columns={'A':'a'})
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C |
beijing |
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SH |
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GZ |
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回顾python 的Map函数
list1 = [1,2,3,4]
list2 = ['1','2','3','4']
[str(x) for x in list1]
['1', '2', '3', '4']
map(str, list1)
<map at 0x128edbf10>
list(map(str, list1))
['1', '2', '3', '4']
写一个自己的Map函数
df1
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BJ |
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SH |
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GZ |
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def test_map(x):
return x + '_ABC'
df1.index.map(test_map)
Index(['BJ_ABC', 'SH_ABC', 'GZ_ABC'], dtype='object')
df1.rename(index=test_map)
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B |
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BJ_ABC |
0 |
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SH_ABC |
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GZ_ABC |
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8 |