将对象元组转换为字符串元组

Question

>>> import MySQLdb
>>> db = MySQLdb.connect( host = "localhost", user ="root", passwd = "", db = "smoky_db" )
>>> cur = db.cursor()
>>> cur.execute( 'SELECT * FROM logs' )
3L
>>> rows = cur.fetchall()
>>> rows
((1L, datetime.datetime(2014, 5, 21, 0, 0)), (1L, datetime.datetime(2014, 5, 22, 0, 0)) )

how can I convert the returned tuples of objects to tuples of strings, Something like this:

(('1', '2014-05-21 00:00:00'), ('2', '2014-05-22 00:00:00'))

Answer 1

Simply iterate the items and convert them to tuples, like this

print tuple(tuple(str(item) for item in items) for items in d)
# (('1', '2014-05-21 00:00:00'), ('1', '2014-05-22 00:00:00'))

Here we have used two generator expressions. The innermost one ( str(item) for item in items ) will be executed for every item in the original tuple. And when the nested items are stringified, we iterate the generator expression and convert that to a tuple again.

Answer 2

Call str on every element:

>>> [tuple(map(str, tup)) for tup in tups]
[('1', '2014-05-21 00:00:00'), ('1', '2014-05-22 00:00:00')]

This works because datetime objects implement __str__ method, being called by str function. From the documentation :

For a date d, str(d) is equivalent to d.isoformat(' ').

Answer 3

这应该可以解决问题：

out = tuple((str(k),str(v)) for (k,v) in rows)