From: Raymond Hettinger <python@rcn.com>
Date: Sun, 10 Oct 2010 05:56:57 +0000 (+0000)
Subject: Issue #10029: Fix sample code in the docs for zip().
X-Git-Tag: v3.1.3rc1~134
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=066e7a974afa8582fde9e1f97d76f76ee9ffc216;p=thirdparty%2FPython%2Fcpython.git

Issue #10029: Fix sample code in the docs for zip().
---

diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index efcac085af3c..e97be7b9d03e 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1220,11 +1220,18 @@ are always available.  They are listed here in alphabetical order.
    iterable argument, it returns an iterator of 1-tuples.  With no arguments,
    it returns an empty iterator.  Equivalent to::
 
-      def zip(*iterables):
-          # zip('ABCD', 'xy') --> Ax By
-          iterables = map(iter, iterables)
-          while iterables:
-              yield tuple(map(next, iterables))
+        def zip(*iterables):
+            # zip('ABCD', 'xy') --> Ax By
+            sentinel = object()
+            iterables = [iter(it) for it in iterables]
+            while iterables:
+                result = []
+                for it in iterables:
+                    elem = next(it, sentinel)
+                    if elem is sentinel:
+                        return
+                    result.append(elem)
+                yield tuple(result)
 
    The left-to-right evaluation order of the iterables is guaranteed. This
    makes possible an idiom for clustering a data series into n-length groups