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authorGeorg Brandl <georg@python.org>2007-09-04 17:58:02 (GMT)
committerGeorg Brandl <georg@python.org>2007-09-04 17:58:02 (GMT)
commitc53c9666f57b83ac0430ce6ca480b58e011e96ea (patch)
tree7e4126c16f9fc7a820a96571c46d35511b953fe6 /Doc
parent952aea2ce6e763c238539e5314885f2938518a4d (diff)
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Add a dict view usage example.
Diffstat (limited to 'Doc')
-rw-r--r--Doc/library/stdtypes.rst30
1 files changed, 30 insertions, 0 deletions
diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 7ec0180..75db75c 100644
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -1906,6 +1906,36 @@ to another dictionary view or a set):
four operations will fail if an involved dictionary contains such a value.
+An example of dictionary view usage::
+
+ >>> dishes = {'eggs': 2, 'sausage': 1, 'bacon': 1, 'spam': 500}
+ >>> keys = dishes.keys()
+ >>> values = dishes.values()
+
+ >>> # iteration
+ >>> n = 0
+ >>> for val in values:
+ ... n += val
+ >>> print(n)
+ 504
+
+ >>> # keys and values are iterated over in the same order
+ >>> list(keys)
+ ['eggs', 'bacon', 'sausage', 'spam']
+ >>> list(values)
+ [2, 1, 1, 500]
+
+ >>> # view objects are dynamic and reflect dict changes
+ >>> del dishes['eggs']
+ >>> del dishes['sausage']
+ >>> list(keys)
+ ['spam', 'bacon']
+
+ >>> # set operations
+ >>> keys & {'eggs', 'bacon', 'salad'}
+ {'eggs', 'bacon'}
+
+
.. _bltin-file-objects:
File Objects