Checking if a list contains a sublist

Question

I'm working on the following practice problem from codingbat:

Given an array of ints, return True if .. 1, 2, 3, .. appears in the array somewhere.

I've written:

def array123(nums):
    array = [1,2,3]
    for i in nums:
        sub = nums[i:i+3] 
        if array == sub:
            return True
     return False

It keeps failing when the string is [1,2,3], any other combination of numbers works. I understand the solution codingbat gives, but I don't understand why my code is only failing in that instance. What am I doing wrong?

Answer 1

for i in nums: successively assigns to i the value of the items of list nums .

However you appear to believe it's assigning indices rather than value -- perhaps that's because it's what it the equivalent construct would to in Javascript.

So make i iterate over the indices -- for i in range(len(nums)-3): and the rest of your code seems fine!