Guido van Rossum added the comment:

Just like for other binary operators (except for the ones mentioned as always 
needing spaces), the spaces around ":" are neither mandatory nor objectionable. 
 I am not making up a new rule, this is how I've always thought -- we just have 
to make it explicit that x[1: n] is wrong.

How about this:

- However, in a slice the colon acts like a binary operator, and
  should have equal amounts on either side (treating it as the
  operator with the lowest priority).  In an extended slice, both
  colons must have the same amount of spacing applied.  Exception:
  when a slice parameter is omitted, the space is omitted. ::

  Yes::

      ham[1:9], ham[1:9:3], ham[:9:3], ham[1::3], ham[1:9:]
      ham[lower:upper], ham[lower:upper:], ham[lower::step]
      ham[lower+offset : upper+offset]
      ham[: upper_fn(x) : step_fn(x)], ham[:: step_fn(x)]
      ham[lower + offset : upper + offset]

  No::

      ham[lower + offset:upper + offset]
      ham[1: 9], ham[1 :9], ham[1:9 :3]
      ham[lower : : upper]
      ham[ : upper]

----------

_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue22316>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

Reply via email to