如何更新/在列表中的基于价值的大熊猫创建列

Question

所以，这里是我的数据框

import pandas as pd 
cols = ['Name','Country','Income'] 
vals = [['Steve','USA',40000],['Matt','UK',40000],['John','USA',40000],['Martin','France',40000],] 
x = pd.DataFrame(vals,columns=cols) 

我有另外一个列表：

europe = ['UK','France'] 

我想创建一个新列“大陆如果x.Country是在欧洲

Answer 1

，也可以使用isin直接

x['New Column']='Not Europe' 
x.loc[x.Country.isin(europe),'New Column']='Europe' 

Out[612]: 
    Name Country Income New Column 
0 Steve  USA 40000 Not Europe 
1 Matt  UK 40000  Europe 
2 John  USA 40000 Not Europe 
3 Martin France 40000  Europe 

Answer 2

您需要numpy.where与条件与isin：

x['Continent'] = np.where(x['Country'].isin(europe), 'Europe', 'Not Europe') 
print (x) 
    Name Country Income Continent 
0 Steve  USA 40000 Not Europe 
1 Matt  UK 40000  Europe 
2 John  USA 40000 Not Europe 
3 Martin France 40000  Europe