CODEWITHSUNDEEP
pythonclassarraylistcontains
Devon
Devon

Reputation: 55

How to successfully implement my own __contains__ method for an ArrayList class?

I'm a relatively new python programmer and am trying to fix my contains method in my ArrayList class. I want to check if an input value is actually contained in the stored list.

def __contains__(self, value):
        """Implements `val in self`. Returns true if value is found in this list."""
        for num in iter(self):
            if(num==value):
                return True
            else: 
                return False

Could someone tell me what might be wrong with this code? I test it with a generated list range(100) for the value 50 but it won't return True.

Upvotes: 0

Views: 59

Answers (1)

Alex Hall
Alex Hall

Reputation: 36033

This tests if num is equal to the first value in self. You should only return False after the whole loop ends and you've shown that num wasn't equal to anything in the list since you haven't returned True yet.

Also note that the iter is implied if you just write for num in self. And a normal Python list ([]) is essentially a Java ArrayList already.

Upvotes: 1

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