Series.map
Series.map(arg, na_action=None)
根据输入对应关系映射系列的值。
用于将Series中的每个值替换为另一个值,该值可能来自函数、dict或Series。
Parameters
arg | 映射关系 |
---|---|
na_action | ignore:忽略NaN值 |
Example
import pandas as pd
df = pd.DataFrame({'site':['google', 'baidu', 'wiki', 'pandas'],
'color': ['red', 'black', None, 'red']})
df.site = df.site.map({'google': 'facebook', 'baidu': 'bing'})
df
--------------------------------------------------------------------
site color
0 facebook red
1 bing black
2 NaN None
3 NaN red
Example
import pandas as pd
df = pd.DataFrame({'site':['google', 'baidu', 'wiki', 'pandas'],
'color': ['red', 'black', None, 'red']})
df.site = df.site.map('I like {}'.format)
df
------------------------------------------------------
site color
0 I like google red
1 I like baidu black
2 I like wiki None
3 I like pandas red
Example
import pandas as pd
df = pd.DataFrame({'site':['google', 'baidu', 'wiki', 'pandas'],
'color': ['red', 'black', None, 'red']})
df.color = df.color.map('I like {}'.format, na_action='ignore')
df
site color
0 google I like red
1 baidu I like black
2 wiki None
3 pandas I like red
Example
import pandas as pd
df = pd.DataFrame({'site':['google', 'baidu', 'wiki', 'pandas'],
'color': ['red', 'black', None, 'red']})
df.color = df.color.map(lambda x: "blue" if x is None else x)
df
site color
0 google red
1 baidu black
2 wiki blue
3 pandas red