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@ -27,8 +27,33 @@ rationale, refer to the PEP for a particular new feature.
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%======================================================================
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\section{PEP 322: Reverse Iteration}
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% Large, PEP-level features and changes should be described here.
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A new built-in function, \function{reversed(seq)}, takes a sequence
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and returns an iterator that returns the elements of the sequence
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in reverse order.
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\begin{verbatim}
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>>> for i in reversed([1,2,3]):
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... print i
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...
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3
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2
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1
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\end{verbatim}
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Note that \function{reversed()} only accepts sequences, not arbitrary
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iterators. If you want to reverse an iterator, convert it to
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a list or tuple with \function{list()} or \function{tuple()}.
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\begin{verbatim}
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>>> input = open('/etc/passwd', 'r')
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>>> for line in reversed(list(input)):
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... print line
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...
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root:*:0:0:System Administrator:/var/root:/bin/tcsh
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...
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\end{verbatim}
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%======================================================================
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@ -76,6 +101,23 @@ The \var{reverse} parameter should have a Boolean value. If the value is
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of \code{L.sort() ; L.reverse()}, you can now write
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\code{L.sort(reverse=True)}.
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\item The list type gained a \method{sorted(iterable)} method that
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returns the elements of the iterable as a sorted list. It also accepts
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the \var{cmp}, \var{key}, and \var{reverse} keyword arguments, same as
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the \method{sort()} method. An example usage:
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\begin{verbatim}
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>>> L = [9,7,8,3,2,4,1,6,5]
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>>> list.sorted(L)
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[1, 2, 3, 4, 5, 6, 7, 8, 9]
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>>> L
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[9, 7, 8, 3, 2, 4, 1, 6, 5]
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>>>
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\end{verbatim}
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Note that the original list is unchanged; the list returned by
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\method{sorted()} is a newly-created one.
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\item The \function{zip()} built-in function and \function{itertools.izip()} now return an empty list
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instead of raising a \exception{TypeError} exception if called
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with no arguments.
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@ -114,6 +156,9 @@ details.
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supports transparency, this makes it possible to use a transparent background.
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(Contributed by J\"org Lehmann.)
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\item The \module{heapq} module is no longer implemented in Python,
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having been converted into C.
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\item The \module{random} module has a new method called \method{getrandbits(N)}
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which returns an N-bit long integer.
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