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
6
votes
3 answers
most common 2-grams using python
Given a string:
this is a test this is
How can I find the top-n most common 2-grams? In the string above, all 2-grams are:
{this is, is a, test this, this is}
As you can notice, the 2-gram this is appears 2 times. Hence the result should be:
{this…
stfd1123581321
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5
votes
3 answers
Cast dict to defaultdict
The following code uses the {} operator to combine two defaultdicts.
from collections import defaultdict
aa=defaultdict(str)
bb=defaultdict(str)
aa['foo']+= '1'
bb['bar']+= '2'
cc = {**aa,**bb}
type(cc)
But, as we see if we run this, the {}…
Ray Salemi
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5
votes
2 answers
Counter allowing repetitions
I have a Traffic Light Enum defining possible states:
class TrafficLightPhase(Enum):
RED = "RED"
YELLOW = "YELLOW"
GREEN = "GREEN"
I poll a Traffic Light to get current state every second and I put the values in a deque with this…
logoff
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5
votes
3 answers
python multiply two collection counters
Python collection counter
Curious if there is a better way to do this. Overriding a Counter class method?
The built-in multiply produces the dot product of two counters
from collections import Counter
a = Counter({'b': 4, 'c': 2, 'a': 1})
b =…
codervince
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5
votes
1 answer
Why is collections.Counter uppercase and collections.defaultdict is not?
Some of the elements in the collections module seem to be uppercase, some other not. Is there a specific rationale behind it?
meto
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5
votes
2 answers
collections.Counter: most_common INCLUDING equal counts
In collections.Counter, the method most_common(n) returns only the n most frequent items in a list. I need exactly that but I need to include the equal counts as well.
from collections import Counter
test =…
KarelCote
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5
votes
3 answers
Python Counter Comparison as Bag-type
I need a bag/multiset-like data type in Python. I understand collections.Counter is often used for this purpose. But the comparison operators don't seem to work:
In [1]: from collections import Counter
In [2]: bag1 = Counter(a=1, b=2, c=3)
In [3]:…
William Reed
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- 4
5
votes
2 answers
Make Counter.most_common return dictionary
I used the sample from the documentation:
>>> Counter('abracadabra').most_common(3)
[('a', 5), ('r', 2), ('b', 2)]
How can I make the result to be:
{ 'a': 5, 'r' :2 , 'b' :2}
supposing that we want to keep the Counter().most_common() code?
Diolor
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4
votes
3 answers
Algorithmic complexity to convert a set to a list in python
In python, when I convert my set to a list, what is the algorithmic complexity of such a task? Is it merely type-casting the collection, or does it need to copy items into a different data structure? What's happening?
I'd love to learn that the…
macetw
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4
votes
1 answer
key function for heapq.nlargest()
I have a dictionary with {key: count}, say
status_count = {'MANAGEMENT ANALYSTS': 13859, 'COMPUTER PROGRAMMERS': 72112}
and I am trying to write a key function for heapq.nlargest() that sorts based on count and if there are ties I have to sort based…
pulsar
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4
votes
2 answers
Python append Counter to Counter, like Python dictionary update
I have 2 Counters (Counter from collections), and I want to append one to the other, while the overlapping keys from the first counter would be ignored. Like the dic.update (python dictionaries update)
For example:
from collections import Counter
a…
sheldonzy
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4
votes
4 answers
python set union operation is not behaving well with named tuples
I want to create a set of namedtuple in python, with the ability to add elements dynamically using the union operation.
The following code snippet creates a set of namedtuple, which is behaving nicely.
from collections import namedtuple
B =…
Jayendra Parmar
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4
votes
2 answers
Inherit from collections.Counter: 'fromkeys' is abstract
I have a python class that inherit from collections.Counter:
class Analyzer(collections.Counter):
pass
When I use pylint on this code, its answer is:
W: Method 'fromkeys' is abstract in class 'Counter' but is not overridden…
audeoudh
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4
votes
4 answers
Print first Key Value in an Ordered Counter
I am trying to print out the Key Value pair in the same order as displayed in the OrderedCounter Output.
from collections import Counter, OrderedDict
class OrderedCounter(Counter, OrderedDict):
pass
c = OrderedCounter('supernatural')
print…
Vishwak
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4
votes
1 answer
Why doesn't OrderedDict use super?
We can create an OrderedCounter trivially by using multiple inheritance:
>>> from collections import Counter, OrderedDict
>>> class OrderedCounter(Counter, OrderedDict):
... pass
...
>>> OrderedCounter('Mississippi').items()
[('M', 1), ('i',…
wim
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