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+--- Thread: Error in the method "count" for tuple (/thread-43580.html)
Error in the method "count" for tuple - fff - Nov-23-2024
I just wrote this simple code to count the number of 1 in this tuple. Ironically, it returns 2 instead of 1. I have the last version of Python. Also, I checked the program with Colab, and I got the same wrong result. It is interesting that this problem occurs only for "1"!!
mixed_tuple = (1, 3.4, "ali", True, [0, 3, 3]) print(mixed_tuple.count(1))The result will be 2.
RE: Error in the method "count" for tuple - DeaD_EyE - Nov-23-2024
Oh, yes and the result is right.
In [1]: 1 == True Out[1]: True In [2]: int.mro() Out[2]: [int, object] In [3]: bool.mro() Out[3]: [bool, int, object] In [4]: ((1,)).count(1) Out[4]: 1 In [5]: ((1, True)).count(1) Out[5]: 2 In [6]: ((0, True)).count(1) Out[6]: 1 In [7]: ((0, False)).count(1) Out[7]: 0 In [8]: ((0, False)).count(0) Out[8]: 2A boolean is a subtype of int.
It's getting worse, if you use for keys boolean and int as keys:
In [1]: d = {0: "Foo"}
In [2]: print(d)
{0: 'Foo'}
In [3]: d[False] = "This is False"
In [4]: # now what do you expect?
In [5]: print(d)
{0: 'This is False'}Do not mix int with bool in sequences and mappings.Sometime the property could be easily used.
If you have a list/tuple with only boolean insde, you can sum up True, which is a subtype of int and is equal to 1.
In [1]: import random In [2]: data = random.choices([True, False], k=10) In [3]: print(data) [True, False, False, False, True, False, True, True, False, True] In [4]: # count number of True In [5]: print(sum(data)) 5
RE: Error in the method "count" for tuple - fff - Nov-24-2024
Thank you for your detailed response.