Python string.split for循环中有多个值

Question

基本上这很好用:

>>> x,y = "x=y".split("=")
>>> print x
x

但是这给出了一个错误:

>>> for x, y in "x=y".split("="):
...     print x
...

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: need more than 1 value to unpack

我想知道有什么区别,以及我如何解决这个问题.

Answer 1

拆分为"="会给出两个值:

"x", "y"

这些值与您的变量名匹配的事实是偶然的.你也可以这样做:

x,xx = "x=y".split("=")

我怀疑你可能计划的是列出一个清单:

"foo=bar,blah=boo,etc=something"

拆分它,你可以做到:

for x,y in [ (pair.split("=")) for pair in "foo=bar,blah=boo,etc=something".split(",") ]:
    print x,y

但!虽然它有效,但我认为将它分成单独的步骤要好得多,因为它更具可读性:

params = "foo=bar,blah=boo,etc=something"
pair_list = params.split(",")
for pair in pair_list:
    x,y = pair.split("=")
    ...