[Python-checkins] peps: Clarify space around colon in slice (severa cases).

Mon Sep 1 05:19:09 CEST 2014

http://hg.python.org/peps/rev/e98737176f1d
changeset: 5538:e98737176f1d
user: Guido van Rossum <guido at python.org>
date: Sun Aug 31 20:18:33 2014 -0700
summary:
 Clarify space around colon in slice (severa cases).
files:
 pep-0008.txt | 25 +++++++++++++++++++++++--
 1 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/pep-0008.txt b/pep-0008.txt
--- a/pep-0008.txt
+++ b/pep-0008.txt
@@ -408,6 +408,27 @@
 Yes: if x == 4: print x, y; x, y = y, x
 No: if x == 4 : print x , y ; x , y = y , x
 
+- 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]
+
 - Immediately before the open parenthesis that starts the argument
 list of a function call::
 
@@ -417,8 +438,8 @@
 - Immediately before the open parenthesis that starts an indexing or
 slicing::
 
- Yes: dict['key'] = list[index]
- No: dict ['key'] = list [index]
+ Yes: dct['key'] = lst[index]
+ No: dct ['key'] = lst [index]
 
 - More than one space around an assignment (or other) operator to
 align it with another.
-- 
Repository URL: http://hg.python.org/peps
