Python print statement not executing

Question

I have a function that I'm calling from my main function.

def generate_new(tokens, outfile):
    print('NO')
    new_sents = []
    for i in range(0, len(tokens)):
        first = tokens[i]
        second = tokens[i]
    print('YES')

This is working fine. However, when I'm adding one more statement, only the first print gets executed.

def generate_new(tokens, outfile):
    print('NO')
    new_sents = []
    for i in range(0, len(tokens)):
        first = tokens[i]
        second = tokens[i+1]
        first_found = first
    print('YES')

I've already tried flushing the buffer. I suspect it's an indentation issue but this code was running fine previously. I added some statements to the end of the function and since then it never executes the statements outside the loop. What could be the issue? Thank you.

Answer 1

The issue is that you are accessing the list tokens out of bounds,

range(0, len(tokens)) goes from 0 to len(tokens)-1

Now when you access tokens[i+1] , it throws an index out of bound exception and execution stops. As a result nothing after the loop gets executed.

You should be able to see the Exception on the console.

Anyway, the fix -

Either change the logic or iterate only till len(tokens)-1

I hope that explains the issue.