Python:将元组转换为逗号分隔的字符串

问题描述：

import MySQLdb

db = MySQLdb.connect("localhost","root","password","database")
cursor = db.cursor()
cursor.execute("SELECT id FROM some_table")
u_data = cursor.fetchall()

>>> print u_data
((1320088L,),)

我在互联网上找到的东西让我到这里为止:

What I found on internet got me till here:

string = ((1320088L,),)
string = ','.join(map(str, string))
>>> print string
(1320088L,)

我希望输出结果如下:

 #Single element expected result
 1320088L  
 #comma separated list if more than 2 elements, below is an example
 1320088L,1320089L

答

首先使用itertools.chain_fromiterable()展平嵌套的元组，然后使用map()展平字符串和join().请注意，str()删除了L后缀，因为数据不再是long类型.

Use itertools.chain_fromiterable() to flatten your nested tuples first, then map() to string and join(). Note that str() removes the L suffix because the data is no longer of type long.

>>> from itertools import chain
>>> s = ((1320088L,),)
>>> ','.join(map(str,chain.from_iterable(s)))
'1320088'

>>> s = ((1320088L,1232121L),(1320088L,),)
>>> ','.join(map(str,chain.from_iterable(s)))
'1320088,1232121,1320088'

请注意，string不是一个好的变量名，因为它与 string 模块.

Note, string is not a good variable name because it is the same as the string module.

Python:将元组转换为逗号分隔的字符串

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