diff options
Diffstat (limited to 'Doc/whatsnew')
| -rw-r--r-- | Doc/whatsnew/whatsnew24.tex | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/Doc/whatsnew/whatsnew24.tex b/Doc/whatsnew/whatsnew24.tex index 68742a8..23c3431 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') |