A Python module that implements specialized container datatypes providing alternatives to Python’s general purpose built-in containers, dict, list, set, and tuple.
Questions tagged [python-collections]
129 questions
2
votes
0 answers
Proper way to document that a class implements a collections interface?
Assuming I have a class that implements the Sequence interface, i.e. has __len__ and __getitem__ methods, what is the recommended way to document this? Is an informal description in the classes docstring enough, should I subclass…
gmolau
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2
votes
1 answer
Which method is called when adding a key to a dict?
I would like to inherit the OrderedDict class to set up a maximum length to the dict.
I did :
from collections import OrderedDict
class limitedDict(OrderedDict):
def __init__(self, length):
OrderedDict.__init__(self)
…
Romain Jouin
- 4,448
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2
votes
3 answers
retrieve input of collections.Counter output
Not sure if the title is correct but.
Lets say you have a list that would look like the output from a Counter object.
[(-3.0, 4), (-2.0, 1), (-1.0, 1), (0.0, 1), (1.0, 1), (2.0, 1), (3.0, 4)]
How could I go back and get the original list, as
[-3.0,…
Isbister
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2
votes
1 answer
Why am I getting and adding behavior on a recursive method?
I am trying to generate XML with xmltodict. To do this I need to generate structures based on OrderedDict. I get the expected behavior the first time I execute my ".xml()" method but when I execute a second time I get the children elements added a…
luisfernando
- 117
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1
vote
1 answer
Test if collections.Mapping is equal to other mapping, or dict
I have written a custom mapping class that inherits from collections.Mapping. Is there an easy way to test if an instance's data is equal to another mapping object, e.g. dict?
Gary van der Merwe
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1
vote
1 answer
Create a dictionary by entering a word and its meaning then print it at the end
This is the question:
and this the output that is required:
This is code I have written so far:
class_list = []
keys = []
meanings = []
def script():
key = input("Enter the word: ")
no_meanings = int(input("\nEnter the no of meanings:…
carlos
- 45
- 4
1
vote
1 answer
Python list comprehension optimization
I have used during a problem this piece of code to retrieve the count of each element in a list :
nums = [1,1,3,2,3,3,4,1,1,4,2,3,3,2,1,3,4,1,2]
print([nums.count(num) for num in set(nums)])
This code works well but doesn't look like to be as…
Lukas Laudrain
- 436
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1
vote
2 answers
max on collections.Counter
The max on collections.Counter is counter intuitive, I want to find the find the character that occurs the most in a string.
>>> from collections import Counter
>>> c = Counter('aaaabbbcc')
>>> max(c)
'c'
>>> c
Counter({'a': 4, 'b': 3, 'c': 2})
I…
Data Cyclist
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1
vote
1 answer
Sequence vs. MutableSequence
I've been using Sequence in type hints for sequences including mutable lists. Now I've just discovered that there is also MutableSequence. As far as I can tell, Sequence is a superclass of MutableSequence, i.e., Sequence includes both mutables like…
flotzilla
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1
vote
1 answer
Python 3.9.5: One dictionary assignment is overwriting multiple keys [BUG?]
I am reading a .csv called courses. Each row corresponds to a course which has an id, a name, and a teacher. They are to be stored in a Dict. An example:
list_courses = {
1: {'id': 1, 'name': 'Biology', 'teacher': 'Mr. D'},
...
}
While…
KuboMD
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1
vote
1 answer
Way to achieve str.strip()-like behaviour with iterable Python-objects
Which is the way is to achieve str.strip()-like behaviour with list, tuple and similar iterable objects in Python?
Examples:
str.strip()-like
>>> lst = ['\t', 0, 'a', ' ', 0, '\n', '\n', '', '\t']
>>> list_strip(lst)
... [0, 'a', ' ', 0]
>>>…
dinya
- 1,563
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1
vote
2 answers
How to access elements in a dict_values?
I have a dict :
{49: {'created_at': '2018-11-07T13:25:12.000Z', 'url': 'https://www.test.com'}}
I would like to get 'created_at'.
I've attempt through different methods but without a success... I thought this approach would works:
result =…
Grégoire de Kermel
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1
vote
1 answer
python counting elements in iterable with filter
To count the elements in a list, you can use collections.Counter, but what if only some of the elements have to be counted?
I've set up this example (please note: numpy is just for convenience. In general the list will contain arbitrary python…
lhk
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1
vote
3 answers
Convert 2-column counter-like csv file to Python collections.Counter?
I have a comma separated (,) tab delimited (\t), file.
68,"phrase"\t
485,"another phrase"\t
43, "phrase 3"\t
Is there a simple approach to throw it into a Python Counter?
GollyJer
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1
vote
1 answer
Why do I have to instantiate a python deque of namedtuples as a list?
I have a queue of nodes that I need to have an upper and lower bound to them, so I have a named tuple called QueueEntry.
QueueEntry = collections.namedtuple('QueueEntry', ('node', 'lower', 'upper'))
When I instantiate a deque with the named tuple…
user22261
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