pandas.map

Series. map ( arg, na_action=None ) [source] ¶

Map values of Series using input correspondence (which can be a dict, Series, or function)

Parameters:	arg : function, dict, or Series na_action : {None, ‘ignore’} If ‘ignore’, propagate NA values, without passing them to the mapping function
Returns:	y : Series same index as caller

Examples

Map inputs to outputs

复制代码>>> x one 1 two 2 three 3

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>>> x
one
1
two
2
three 3

复制代码>>> y 1 foo 2 bar 3 baz

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>>> y
1
foo
2
bar
3
baz

复制代码>>> x.map(y) one foo two bar three baz

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>>> x.map(y)
one
foo
two
bar
three baz

Use na_action to control whether NA values are affected by the mapping function.

复制代码>>> s = pd.Series([1, 2, 3, np.nan])

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>>> s = pd.Series([1, 2, 3, np.nan])

复制代码>>> s2 = s.map(lambda x: 'this is a string {}'.format(x), na_action=None) 0 this is a string 1.0 1 this is a string 2.0 2 this is a string 3.0 3 this is a string nan dtype: object

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>>> s2 = s.map(lambda x: 'this is a string {}'.format(x),

na_action=None)
0
this is a string 1.0
1
this is a string 2.0
2
this is a string 3.0
3
this is a string nan
dtype: object

复制代码>>> s3 = s.map(lambda x: 'this is a string {}'.format(x), na_action='ignore') 0 this is a string 1.0 1 this is a string 2.0 2 this is a string 3.0 3 NaN dtype: object

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>>> s3 = s.map(lambda x: 'this is a string {}'.format(x),

na_action='ignore')
0
this is a string 1.0
1
this is a string 2.0
2
this is a string 3.0
3
NaN
dtype: object

最后

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