[Python] A program that calculates the number of socks to be paired

[Python] A program that calculates the number of socks to be paired

This is a memo for myself.

▼ Question

--There is a list that contains any number of integers. --The values in the list represent the color numbers of the socks. --One set when two of the same color are available. --Calculate the number of sets.


▼sample input


10 20 20 10 10 30 50 10 20

▼sample output



▼my answer


def sockMerchant(n, ar):
    for i in set(ar):
        pair += int(ar.count(i)/2)
    return pair

if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')
    n = int(input())
    ar = list(map(int, input().rstrip().split()))
    result = sockMerchant(n, ar)
    fptr.write(str(result) + '\n')

** ・ int () ** ** Truncate ** after the decimal point

** ・ count method ** Object.count (i) Returns the number of i's in the object.

It can also be used as a character string.


aaa = "Ai Ue Ai Ue Ai"

## Keep it simple with comprehensions

▼ my answer (included notation)



def sockMerchant(n, ar):
    return sum([int((ar.count(i))/2) for i in set(ar)])

sockMerchant(9, ar)

--Substitutions such as "+ =" cannot be used in comprehensions. -In case of [], list type is returned. --sum (list) returns the total value of each element of list

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