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python Programming Glossary: defaultdict

Python: Change values in dict of nested dicts using items in a list

http://stackoverflow.com/questions/11918852/python-change-values-in-dict-of-nested-dicts-using-items-in-a-list

'abcd' d d 'a' 'b' 'c' 'd' 4 True from collections import defaultdict autovivify lambda defaultdict autovivify d autovivify set_value.. True from collections import defaultdict autovivify lambda defaultdict autovivify d autovivify set_value d 'abc' 'd' 4 reduce dict.get..

Check if a given key already exists in a dictionary

http://stackoverflow.com/questions/1602934/check-if-a-given-key-already-exists-in-a-dictionary

to always ensure a default value for any key you can use defaultdict from the collections module like so from collections import.. the collections module like so from collections import defaultdict d defaultdict lambda 0 for i in xrange 100 d i 10 1 ... but.. module like so from collections import defaultdict d defaultdict lambda 0 for i in xrange 100 d i 10 1 ... but in general the..

Random weighted choice

http://stackoverflow.com/questions/2073235/random-weighted-choice

a Cumulative Distribution Function for each ID1 thus cdfs defaultdict for id1 id2 val in d prevtotal cdfs id1 1 0 newtotal prevtotal..

when does Python allocate new memory for identical strings?

http://stackoverflow.com/questions/2123925/when-does-python-allocate-new-memory-for-identical-strings

S from __future__ import division from collections import defaultdict from copy import copy import cPickle import random import sys..

Python - Is a dictionary slow to find frequency of each character?

http://stackoverflow.com/questions/2522152/python-is-a-dictionary-slow-to-find-frequency-of-each-character

load files. approach american english big.txt time w.r.t. defaultdict time seconds time seconds Counter 0.451 3.367 3.6.. 2.5 list 0.277 1.822 2 try except 0.158 1.068 1.2 defaultdict 0.141 0.925 1 numpy 0.012 0.076 0.082 S.Mark's ext. 0.003.. that compares 'Counter' 'setdefault' 'list' 'try except' 'defaultdict' 'numpy' 'cython' based and @S.Mark's solutions is at http gist.github.com..

Printing all instances of a class

http://stackoverflow.com/questions/328851/printing-all-instances-of-a-class

control. Use a mixin and weakrefs from collections import defaultdict import weakref class KeepRefs object __refs__ defaultdict list.. defaultdict import weakref class KeepRefs object __refs__ defaultdict list def __init__ self self.__refs__ self.__class__ .append..

Setting smaller buffer size for sys.stdin?

http://stackoverflow.com/questions/3670323/setting-smaller-buffer-size-for-sys-stdin

times # usr bin python import sys from collections import defaultdict if __name__ __main__ keys defaultdict int GET 1 SET 2 CLIENT.. collections import defaultdict if __name__ __main__ keys defaultdict int GET 1 SET 2 CLIENT 1 SERVER 2 #if for line in sys.stdin..

Check if a given index already exists in a dictionary and increment it

http://stackoverflow.com/questions/473099/check-if-a-given-index-already-exists-in-a-dictionary-and-increment-it

improve this question You are looking for collections.defaultdict available for Python 2.5 . This from collections import defaultdict.. available for Python 2.5 . This from collections import defaultdict my_dict defaultdict int my_dict key 1 will do what you want... 2.5 . This from collections import defaultdict my_dict defaultdict int my_dict key 1 will do what you want. By the way if there..

python dict.add_by_value(dict_2)?

http://stackoverflow.com/questions/877295/python-dict-add-by-valuedict-2

performance I'd do the following from collections import defaultdict def d_sum a b d defaultdict int a for k v in b.items d k v.. from collections import defaultdict def d_sum a b d defaultdict int a for k v in b.items d k v return dict d a 'a' 1 'b' 2..

item frequency count in python

http://stackoverflow.com/questions/893417/item-frequency-count-in-python

count frequency counting share improve this question defaultdict to the rescue from collections import defaultdict words apple.. defaultdict to the rescue from collections import defaultdict words apple banana apple strawberry banana lemon d defaultdict.. words apple banana apple strawberry banana lemon d defaultdict int for word in words.split d word 1 This runs in O n . share..