python - 如何根据某些条件更改 pandas 中的列值

Question

当数据框中的列值匹配某些特定条件时，我想将其更改为另一个名称。

我尝试在数据帧上应用方法，但没有成功。

这是我拥有的数据集，我希望在某些情况下应更改国家/地区列名称。例如，“韩国”应更改为“韩国”，我有类似的名称需要在此栏中更改。我尝试了应用方法，但没有得到任何结果。任何建议都会对我有帮助。先感谢您。 **

df.head()

       Country Energy_Supply Energy_Supply_per_Capita   
0      Afghanistan      3.210000e       10.0    
1      Albania          1.020000e       35.0    
2      Algeria          1.959000e+09    51.0    
3      American Samoa   NaN             NaN 

Answer 1

您可以使用replace()为您感兴趣的专栏。 创建字典 repl_dict = {"中华民国": "中国", "摩尔多瓦共和国": "摩尔多瓦", "法兰西共和国": "法国","英国": "英格兰"} 然后pass就是替换函数，更多详情和参数查看pandas.DataFrame.replace

This method does replace all at once by creating the dictionary with all the names of interest, ultimately will standardize your dataframe column based on this dictionary and no need to run individually for each Country.

import pandas as pd
my_dict = { 'Country' : ["Republic of China", "China", "England", "Republic of Moldova", "Republic of France","Great Britain", "England"],
                   'age' : [20,27, 35, 55, 18, 21, 35],
                   'designation': ["VP", "CEO", "CFO", "VP", "VP", "CEO", "MD"]}

dfnew = pd.DataFrame(my_dict)
print(dfnew)

Country  age designation
0    Republic of China   20          VP
1                China   27         CEO
2              England   35         CFO
3  Republic of Moldova   55          VP
4   Republic of France   18          VP
5        Great Britain   21         CEO
6              England   35          MD

repl_dict = {"Republic of China": "China", "Republic of Moldova": "Moldova", "Republic of France": "France","Great Britain": "England"}
dfnew['Country'] = dfnew['Country'].replace(repl_dict, regex=True)
print()
print('Final dataframe', dfnew)

Final dataframe    
Country  age designation
0    China   20          VP
1    China   27         CEO
2  England   35         CFO
3  Moldova   55          VP
4   France   18          VP
5  England   21         CEO
6  England   35          MD