CODEWITHSUNDEEP
pythonalgorithm
Sung Yeon Park
Sung Yeon Park

Reputation: 93

Error saying "cannot unpack non-iterable int object"

class Tests():

    def genes():
        t=int(input())
        for i in range(t):
            num = int(input())
            numbers = list(map(int,input().strip().split()))
            return num, numbers

    def solve(num, numbers):
        while num>0:  
            profit = 0
            while numbers:

                pos = numbers.index(max(numbers))
                for i in range(pos):
                    profit += (max(numbers)-numbers[i])
                numbers = numbers[pos+1::]
                num -= 1
            return profit


    if __name__ == "__main__":
        for num, numbers in genes():
            print('#{0} {1}'.format(i+1, solve(num, numbers)))

I don't know why "for num, numbers in genes():" causes an error and how to fix this

Upvotes: 0

Views: 374

Answers (1)

ShadowRanger
ShadowRanger

Reputation: 155438

genes() is returning the first tuple of num, numbers and nothing else. I suspect you intended it to generate all pairings, so you could actually iterate over multiple results, unpacking each as you go to num and numbers in the caller. To do so, change return to yield to make it a generator function:

def genes():
    t=int(input())
    for i in range(t):
        num = int(input())
        numbers = list(map(int,input().strip().split()))
        yield num, numbers  # Only change

The problem was caused because you effectively said:

for num, numbers in (genes_num, genes_numbers):

causing it to try to unpack the single num from genes into num and numbers.

You may want to check your solve function as well; the while num > 0: line will only ever be evaluated once, because you unconditionally return at the bottom of said loop. It's unclear why this should be a while loop at all, given numbers will be exhausted in the inner loop, and without it, any subsequent runs of the outer loop will unconditionally set profit to 0.

I'll also note that defining methods on a class that aren't @staticmethods and don't take self is an issue; you're getting away with it because you run your "main" code in the scope of the class definition (so the class isn't actually involved), but it's distinctly odd. You probably don't need a class at all.

Upvotes: 2

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