mirror of https://github.com/python/cpython
Explain the advantages of reversed.
This commit is contained in:
parent
607c00f792
commit
bc3cba2881
|
@ -34,7 +34,7 @@ and returns an iterator that returns the elements of the sequence
|
||||||
in reverse order.
|
in reverse order.
|
||||||
|
|
||||||
\begin{verbatim}
|
\begin{verbatim}
|
||||||
>>> for i in reversed([1,2,3]):
|
>>> for i in reversed(xrange(1,4)):
|
||||||
... print i
|
... print i
|
||||||
...
|
...
|
||||||
3
|
3
|
||||||
|
@ -42,9 +42,12 @@ in reverse order.
|
||||||
1
|
1
|
||||||
\end{verbatim}
|
\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
|
Note that \function{reversed()} only accepts sequences, not arbitrary
|
||||||
iterators. If you want to reverse an iterator, convert it to
|
iterators. If you want to reverse an iterator, first convert it to
|
||||||
a list or tuple with \function{list()} or \function{tuple()}.
|
a list with \function{list()}.
|
||||||
|
|
||||||
\begin{verbatim}
|
\begin{verbatim}
|
||||||
>>> input = open('/etc/passwd', 'r')
|
>>> input = open('/etc/passwd', 'r')
|
||||||
|
|
Loading…
Reference in New Issue