[英]spliting comma separated values and storing in separate row in python 3.x?
我有以下python列表:
original = [(7782, 'Mandarin, Chinese'),
(7783, 'Italian, Conversational Spanish'),
(7792, 'Spanish, English'),
(7793, 'English, Italian')]
我想要的結果是這樣的:
[(7782, 'Mandarin'),
(7782, 'Chinese'),
(7783, 'Italian'),
(7783, 'Coversational Spanish'),
(7792, 'Spanish'),
(7792, 'English'),
(7793, 'English'),
(7793, 'Italian') ]
我是python的新手。 我該如何實現? 到目前為止,我的代碼如下:
import pymysql
db = pymysql.connect("localhost","root","123456","itutor" )
cursor = db.cursor()
query = "SELECT distinct user_id, language from table;"
cursor.execute(query)
r = list(cursor.fetchall())
db.close()
r2 = r[0][1].split(",")
假設您無法在上游解決問題,則可以使用嵌套列表理解:
res = [(num, lang) for num, languages in original for lang in languages.split(', ')]
[(7782, 'Mandarin'),
(7782, 'Chinese'),
(7783, 'Italian'),
(7783, 'Conversational Spanish'),
(7792, 'Spanish'),
(7792, 'English'),
(7793, 'English'),
(7793, 'Italian')]
要了解其構造方式,請考慮等效的for
循環:
res = []
for num, languages in original:
for lang in languages.split(', '):
res.append((num, lang))
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