From: Raymond Hettinger <python@rcn.com>
Date: Wed, 12 Nov 2003 16:39:30 +0000 (+0000)
Subject: Explain the advantages of reversed.
X-Git-Tag: v2.4a1~1292
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bc3cba2881c4c99fa7cffe7c5bb46b596857f3d6;p=thirdparty%2FPython%2Fcpython.git

Explain the advantages of reversed.
---

diff --git a/Doc/whatsnew/whatsnew24.tex b/Doc/whatsnew/whatsnew24.tex
index 68742a8792a9..23c34319803e 100644
--- a/Doc/whatsnew/whatsnew24.tex
+++ b/Doc/whatsnew/whatsnew24.tex
@@ -34,7 +34,7 @@ and returns an iterator that returns the elements of the sequence
 in reverse order.  
 
 \begin{verbatim}
->>> for i in reversed([1,2,3]):
+>>> for i in reversed(xrange(1,4)):
 ...    print i
 ... 
 3
@@ -42,9 +42,12 @@ in reverse order.
 1
 \end{verbatim}
 
+Compared to extended slicing, \code{range(1,4)[::-1]}, \function{reversed()}
+is easier to read, runs faster, and uses substantially less memory.
+
 Note that \function{reversed()} only accepts sequences, not arbitrary
-iterators.  If you want to reverse an iterator, convert it to 
-a list or tuple with \function{list()} or \function{tuple()}.
+iterators.  If you want to reverse an iterator, first convert it to 
+a list with \function{list()}.
 
 \begin{verbatim}
 >>> input = open('/etc/passwd', 'r')