I have a list whose elements are all dictionaries, and I want to count the total number of elements under specified conditions

Question

I have a list like this:

my_list=[{'is_pass':True},{'is_pass':True},{'is_pass':False},{'is_pass':False},{'is_pass':True},{'is_pass':True}]

I want to calculate the total number of elements, the number of True, and the number of False.

The following method can get what I want, but I think python should have an easier way to calculate the number of True and False respectively.I tried count, Counter, but failed to achieve the purpose, who knows how to get it quickly?

total = len(my_dict)
true_flag = 0
false_flag = 0
for i in my_list:
    if i['is_pass'] == True:
        true_flag += 1
    if i['is_pass'] == False:
        false_flag += 1

Asked By: Tony

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Source

Answer 1

Try the following:

true_flag = sum([1 for i in my_list if i["is_pass"])
false_flag = len(my_list) - true_flag

Answered By: ykerus

Answer 2

You could use the Counter class from the collections library. It’s much easier and effective:

from collections import Counter

my_list=[{'is_pass':True},{'is_pass':True},{'is_pass':False},{'is_pass':False},{'is_pass':True},{'is_pass':True}]    

print(Counter(tok['is_pass'] for tok in my_list))

This returns you with:

Counter({True: 4, False: 2})

Answered By: Kulasangar

I have a list whose elements are all dictionaries, and I want to count the total number of elements under specified conditions

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