python - pandas.replace 与 str.replace 正则表达式冲突。代码顺序

Question

我的任务是删除括号中的所有内容并删除国家/地区名称后面的所有数字。更改几个国家的名称。

例如玻利维亚(多民族国)”应为“玻利维亚”Switzerland17'应该是'瑞士'`。

我的原始代码的顺序是:

dict1 = {
"Republic of Korea": "South Korea",
"United States of America": "United States",
"United Kingdom of Great Britain and Northern Ireland": "United Kingdom",
"China, Hong Kong Special Administrative Region": "Hong Kong"} 

energy['Country'] = energy['Country'].replace(dict1)
energy['Country'] = energy['Country'].str.replace(r' \(.*\)', '')
energy['Country'] = energy['Country'].str.replace('\d+', '')
energy.loc[energy['Country'] == 'United States']

str.replace 部分工作正常。任务已经完成。当我使用最后一行检查我是否成功更改国家/地区名称时。这个原始代码不起作用。但是，如果我将代码的顺序更改为:

energy['Country'] = energy['Country'].str.replace(r'\(.*\)', '')
能源['国家'] = 能源['国家'].str.replace('\d+', '')
能源['国家'] = 能源['国家'].replace(dict1)

然后成功更改国家/地区名称。那么我的正则表达式语法肯定有问题，如何解决这个冲突？为什么会发生这种情况？

Answer 1

问题是您需要regex=True replace用于替换子字符串:

energy = pd.DataFrame({'Country':['United States of America4',
                                  'United States of America (aaa)','Slovakia']})
print (energy)
                          Country
0       United States of America4
1  United States of America (aaa)
2                        Slovakia

dict1 = {
"Republic of Korea": "South Korea",
"United States of America": "United States",
"United Kingdom of Great Britain and Northern Ireland": "United Kingdom",
"China, Hong Kong Special Administrative Region": "Hong Kong"} 

<小时/>

#no replace beacuse no match (numbers and ()) 
energy['Country'] = energy['Country'].replace(dict1)
print (energy)
                          Country
0       United States of America4
1  United States of America (aaa)
2                        Slovakia

energy['Country'] = energy['Country'].str.replace(r' \(.*\)', '')
energy['Country'] = energy['Country'].str.replace('\d+', '')
print (energy)
                    Country
0  United States of America
1  United States of America
2                  Slovakia

print (energy.loc[energy['Country'] == 'United States'])
Empty DataFrame
Columns: [Country]
Index: []

<小时/>

energy['Country'] = energy['Country'].replace(dict1, regex=True)
print (energy)
               Country
0       United States4
1  United States (aaa)
2             Slovakia

energy['Country'] = energy['Country'].str.replace(r' \(.*\)', '')
energy['Country'] = energy['Country'].str.replace('\d+', '')
print (energy)
         Country
0  United States
1  United States
2       Slovakia

print (energy.loc[energy['Country'] == 'United States'])
         Country
0  United States
1  United States

<小时/>

#first data cleaning
energy['Country'] = energy['Country'].str.replace(r' \(.*\)', '')
energy['Country'] = energy['Country'].str.replace('\d+', '')
print (energy)
                    Country
0  United States of America
1  United States of America
2                  Slovakia

#replace works nice
energy['Country'] = energy['Country'].replace(dict1)
print (energy)
         Country
0  United States
1  United States
2       Slovakia

print (energy.loc[energy['Country'] == 'United States'])
         Country
0  United States
1  United States