python - 在 for 循环中使用 str.split 时为 "ValueError too many values to unpack"

Question

我之前遇到过这个错误，原因很明显，但我在处理下面的这段代码时遇到了问题。

#!/usr/bin/python

ACL = 'group:troubleshooters:r,user:auto:rx,user:nrpe:r'

for e in ACL.split(','):
  print 'e = "%s"' % e
  print 'type during split = %s' % type(e.split(':'))
  print 'value during split:  %s' % e.split(':')
  print 'number of elements:  %d' % len(e.split(':'))
  for (one, two, three) in e.split(':'):
      print 'one = "%s", two = "%s"' % (one, two)

我已经添加了这些用于调试的打印语句，并确认拆分正在生成一个 3 元素列表，但是当我尝试将其放入 3 个变量时，我得到:

e = "group:troubleshooters:r"
type during split = <type 'list'>
value during split:  ['group', 'troubleshooters', 'r']
number of elements:  3
Traceback (most recent call last):
  File "/tmp/python_split_test.py", line 10, in <module>
for (one, two, three) in e.split(':'):
ValueError: too many values to unpack

我错过了什么？

Answer 1

也许你应该:

one, two, three = e.split(":")

因为 e.split(":") 已经是一个具有三个值的可迭代对象。

如果你写

for (one, two, three) in something

那么 something 必须是三个值的可迭代对象中的可迭代对象，例如[[1, 2, 3], [4, 5, 6]]，但不是 [1, 2, 3]。