checking duplicates in list using while loop-CodePudding

I'm trying to check for duplicate numbers within a list using only while loops and if statements. For some reason it is returning True for the list [1, 2, 3, 4, 5, 6] and I can't figure out why.

def has_duplicates(xs):
count = 0
while count < len(xs) and len(xs) > 1:
    check = 1
    while check < len(xs):
        if xs[check] == xs[count]:
            return True
        else:
            check  = 1
    count  = 1
return False

CodePudding user response：

In your first algorithm you shouldn't assing to the check variable the value of 1. Otherwise on the second cycle of the loop both count and check will be 1 and you'll be comparing the element [1] of your list with itself, which will always return true.

Instead you should set the check variable to check = count 1. So that you never compare a value with itself.

CodePudding user response：

I get the correct output using your function. However, there are certainly easier ways to get the same result, as:

def has_duplic2(xs):
    return len(set(xs)) != len(xs)