defaultdict Questions
5
Solved
I need a dictionary that is automatically filled with a default value for each accessed key that is missing. I've found defaultdict and some other ways to achieve this, but the problem in my case i...
Eleph asked 26/1, 2021 at 12:59
4
Solved
In the following code:
from collections import defaultdict
confusion_proba_dict = defaultdict(float)
for i in xrange(10):
confusion_proba_dict[i] = i + 10
print confusion_proba_dict
Output i...
Dx asked 24/12, 2016 at 19:21
4
Solved
I'm getting this really strange ImportError when running from collections import defaultdict:
ImportError: cannot import name defaultdict
I'm running python 2.7, and the strange part is that in ...
Merit asked 13/8, 2014 at 14:5
3
Solved
I have created the following class. Package, website and comments are all strings and distroDict is a (string, list) dictionary.
class TableEntry(object):
def __init__(self, package, website, di...
Malvia asked 17/12, 2015 at 3:24
2
Solved
I've seen other Python programmers use defaultdict from the collections module for the following use case:
from collections import defaultdict
s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('bl...
Brisson asked 23/9, 2012 at 20:25
3
Solved
I usually use the following idiom when working with a Python dictionary:
try:
val = dct[key]
except KeyError:
print key, " is not valid"
since for large dictionaries, the statement
if key in ...
Twitt asked 28/1, 2012 at 17:36
12
Solved
Is there a way to make a defaultdict also be the default for the defaultdict? (i.e. infinite-level recursive defaultdict?)
I want to be able to do:
x = defaultdict(...stuff...)
x[0][1][0]
{}
So...
Batey asked 4/10, 2013 at 19:28
6
Solved
I have a dictionary of lists, and it should be initialized with default keys. I guess, the code below is not good (I mean, it works, but I don't feel that it is written in the pythonic way):
d = {...
Diabolic asked 21/3, 2017 at 4:57
5
mapfile = {
1879048192: 0,
1879048193: 0,
1879048194: 0,
1879048195: 0,
1879048196: 4,
1879048197: 3,
1879048198: 2,
1879048199: 17,
1879048200: 0,
1879048201: 1,
1879048202: 0,
1879048...
Persse asked 23/7, 2015 at 8:16
6
A class has a constructor which takes one parameter:
class C(object):
def __init__(self, v):
self.v = v
...
Somewhere in the code, it is useful for values in a dict to know their keys.
I wan...
Thrum asked 26/5, 2010 at 10:55
3
I am writing code for an application where performance is important. I am wondering why defaultdict seems to be faster then setdefault.
I would like to be able to use setdefault, mostly because i ...
Serai asked 28/7, 2016 at 1:13
2
Solved
Is there a way to change the default_factory of a defaultdict (the value which is returned when a non-existent key is called) after it has been created?
For example, when a defaultdict such as
d ...
Aam asked 6/10, 2013 at 16:35
5
Solved
Given the following dictionary:
d = {"a":{"b":{"c":"winning!"}}}
I have this string (from an external source, and I can't change this metaphor).
k = "a.b.c"
I need to determine if the diction...
Whitehead asked 13/9, 2012 at 21:9
3
Solved
I am trying to do something similar to this:
from collections import defaultdict
import hashlib
def factory():
key = 'aaa'
return { 'key-md5' : hashlib.md5('%s' % (key)).hexdigest() }
a = defa...
Cinchonine asked 16/10, 2013 at 8:56
2
Solved
I'm wondering if there's a more clever way to create a default dict from collections.
The dict should have an empty numpy ndarray as default value.
My best result is so far:
import collections
d ...
Tamikatamiko asked 29/7, 2014 at 11:33
10
Solved
I have a defaultdict that looks like this:
dict1 = defaultdict(lambda: defaultdict(int))
The problem is, I can't pickle it using cPickle. One of the solution that I found here is to use module-l...
Jura asked 8/5, 2013 at 11:20
2
Solved
I am trying to convert a list of dot-separated strings, e.g.
['one.two.three.four', 'one.six.seven.eight', 'five.nine.ten', 'twelve.zero']
into a tree (nested lists or dicts - anything that is e...
Collogue asked 14/5, 2013 at 15:52
15
Solved
I've read the examples in python docs, but still can't figure out what this method means. Can somebody help? Here are two examples from the python docs
>>> from collections import defaultd...
Bundesrat asked 5/5, 2011 at 15:45
3
Solved
I am new to python, and i read some code snippet from some place. It's an implementation of counting sort.
The code is as below:
from collections import defaultdict
def sort_colors(A):
ht = {} #...
Musick asked 20/5, 2015 at 17:48
11
Solved
I have a question about idioms and readability, and there seems to be a clash of Python philosophies for this particular case:
I want to build dictionary A from dictionary B. If a specific key doe...
Liverwort asked 22/12, 2010 at 18:48
4
Solved
I have a data-structure which is something like this:
The population of three cities for different year are as follows.
Name 1990 2000 2010
A 10 20 30
B 20 30 10
C 30 10 20
I am using a default...
Towrope asked 17/4, 2012 at 15:57
2
Solved
So the defaultdict documentation mentions that, if an item is missing, the value returned by default_factory "is inserted in the dictionary for the key, and returned." That's great most of the time...
Jodee asked 30/7, 2013 at 20:40
3
Solved
Is there a way to get the original/consistent list of keys from defaultdict even when non existing keys were requested?
from collections import defaultdict
>>> d = defaultdict(lambda: 'de...
Homosexuality asked 30/7, 2017 at 9:11
2
Solved
I have 2 example lists and what I want to achieve is to obtain a nested default dictionary with the sum of the values.
The following code works nice:
from collections import defaultdict
l1 = [1,...
Andes asked 22/12, 2018 at 10:4
4
Solved
Assume I have a list.
temp = ['A', 'B', 'A', 'B', 'A', 'B']
I am looking for a way to join the count of the string inside.
Intended Output:
['A_1', 'B_1', 'A_2', 'B_2', 'A_3', 'B_3']
I was a...
Signpost asked 1/11, 2018 at 9:49
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