CODEWITHSUNDEEP
python
astrochris
astrochris

Reputation: 1866

I have an if statement and pass it, but get an error anyway, python

I have this if statement in python. where if U<0 i want to pass. but if U>0 I want to know if len(U[0])<1. However I get an error when len(U) < 0 on the line if len(U[0])<1: IndexError: index out of bounds. but i thought it was meant to pass this so it should only look for it when len(U)>0. can anyone help?

   if len(U) < 0:
        pass
   else:
        if len(U[0])<1:
            pass
        else:
            Uli=U[0]
            list2.append(Uli)

Upvotes: 0

Views: 61

Answers (1)

Drathier
Drathier

Reputation: 14519

len returns a non-negative integer. Comparing len(U) < 0 will always be false, so pass is never executed.

Instead, it goes into the else branch, where it tries to access the 0th element of the possibly empty list. The error you're seeing is because the list is empty.

Consider changing if len(U) < 0: to if len(U) == 0: or simply if len(U): or if not U:.

Upvotes: 1

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