熊貓：搜索子字符串是否包含字典中的鍵，並返回值

Question

我有一個字典（鍵，值）和一個使用熊貓的數據框。

mydict = {'KULAR LUMPUR' : 'MY',
            'SINGAPORE' : 'SG',
            'HONG KONG' : 'HK',
            'VIETNAM': 'VN'}

和帶有列['Address']的數據框

                              Address
0  234 JALAN ST KULAR LUMPUR MALAYSIA
1       123 BUILDING STREET SINGAPORE
2          67 CANNING VALE, HONG KONG

如果在字典的鍵中找到了子字符串，如何搜索數據框以從字典中獲取值。

例如

                              Address Code
0  234 JALAN ST KULAR LUMPUR MALAYSIA   MY
1       123 BUILDING STREET SINGAPORE   SG
2          67 CANNING VALE, HONG KONG   HK

Answer 1

將regex與str.extract一起使用str.extract和map字典的鍵：

df = pd.DataFrame({'Address': ['234 JALAN ST KULAR LUMPUR MALAYSIA', 
                               '123 BUILDING STREET SINGAPORE', 
                               '67 CANNING VALE, HONG KONG']})

print (df)
                              Address
0  234 JALAN ST KULAR LUMPUR MALAYSIA
1       123 BUILDING STREET SINGAPORE
2          67 CANNING VALE, HONG KONG

mydict = {'KULAR LUMPUR' : 'MY',
            'SINGAPORE' : 'SG',
            'HONG KONG' : 'HK',
            'VIETNAM': 'VN'}

pat = '|'.join(r"\b{}\b".format(x) for x in mydict.keys())
df['Code'] = df['Address'].str.extract('('+ pat + ')', expand=False).map(mydict)

print (df)
                              Address Code
0  234 JALAN ST KULAR LUMPUR MALAYSIA   MY
1       123 BUILDING STREET SINGAPORE   SG
2          67 CANNING VALE, HONG KONG   HK

說明 ：

print (pat)
\bKULAR LUMPUR\b|\bSINGAPORE\b|\bHONG KONG\b|\bVIETNAM\b

\\b被稱為\\b之間匹配詞的詞邊界
| 用於正則表達式OR