diff options
| -rw-r--r-- | Lib/collections.py | 33 |
1 files changed, 15 insertions, 18 deletions
diff --git a/Lib/collections.py b/Lib/collections.py index d41e00becc..dcb3c6c561 100644 --- a/Lib/collections.py +++ b/Lib/collections.py @@ -27,9 +27,9 @@ class OrderedDict(dict): # An inherited dict maps keys to values. # The inherited dict provides __getitem__, __len__, __contains__, and get. # The remaining methods are order-aware. - # Big-O running times for all methods are the same as for regular dictionaries. + # Big-O running times for all methods are the same as regular dictionaries. - # The internal self.__map dictionary maps keys to links in a doubly linked list. + # The internal self.__map dict maps keys to links in a doubly linked list. # The circular doubly linked list starts and ends with a sentinel element. # The sentinel element never gets deleted (this simplifies the algorithm). # Each link is stored as a list of length three: [PREV, NEXT, KEY]. @@ -52,8 +52,8 @@ class OrderedDict(dict): def __setitem__(self, key, value, PREV=0, NEXT=1, dict_setitem=dict.__setitem__): 'od.__setitem__(i, y) <==> od[i]=y' - # Setting a new item creates a new link which goes at the end of the linked - # list, and the inherited dictionary is updated with the new key/value pair. + # Setting a new item creates a new link at the end of the linked list, + # and the inherited dictionary is updated with the new key/value pair. if key not in self: root = self.__root last = root[PREV] @@ -62,8 +62,8 @@ class OrderedDict(dict): def __delitem__(self, key, PREV=0, NEXT=1, dict_delitem=dict.__delitem__): 'od.__delitem__(y) <==> del od[y]' - # Deleting an existing item uses self.__map to find the link which is - # then removed by updating the links in the predecessor and successor nodes. + # Deleting an existing item uses self.__map to find the link which gets + # removed by updating the links in the predecessor and successor nodes. dict_delitem(self, key) link_prev, link_next, key = self.__map.pop(key) link_prev[NEXT] = link_next @@ -89,14 +89,11 @@ class OrderedDict(dict): def clear(self): 'od.clear() -> None. Remove all items from od.' - try: - for node in self.__map.itervalues(): - del node[:] - root = self.__root - root[:] = [root, root, None] - self.__map.clear() - except AttributeError: - pass + for node in self.__map.itervalues(): + del node[:] + root = self.__root + root[:] = [root, root, None] + self.__map.clear() dict.clear(self) # -- the following methods do not depend on the internal structure -- @@ -129,7 +126,7 @@ class OrderedDict(dict): update = MutableMapping.update - __update = update # let subclasses override update without breaking __init__ + __update = update # let subclasses override update without breaking __init__ __marker = object() @@ -193,10 +190,10 @@ class OrderedDict(dict): and values equal to v (which defaults to None). ''' - d = cls() + self = cls() for key in iterable: - d[key] = value - return d + self[key] = value + return self def __eq__(self, other): '''od.__eq__(y) <==> od==y. Comparison to another OD is order-sensitive |