How to find if character is the last character in a string?

Question

How do I efficiently check if a character when inside a for loop is in the last position of a string?

Like:

string = "daffyduck'd"

I would have done this through

for char in string:
  if char == string[-1]:
    break

This however prematurely ends whenever there is a char that matches the last element, so that does not work. I am dealing with pairs of chars, so when inside a for loop, i am doing a current_index and current_index + 1 operation, so without knowing the last element, I will get a string index out of bound error.

Answer 1

I am dealing with pairs of chars, so when inside a for loop, i am doing a current_index and current_index + 1 operation, so without knowing the last element, I will get a string index out of bound error.

If all you want to do is to process two neighboring characters at a time, then don't use the index, and simply zip the actual string with the same string without the first character, like this

>>> input_string = "daffyduck'd"
>>> for char1, char2 in zip(input_string, input_string[1:]):
...     print(char1, char2)
...     
... 
d a
a f
f f
f y
y d
d u
u c
c k
k '
' d

Note: Your original approach also has a problem, what if the last character occurs somewhere in the middle of the string? This condition will make the loop break immediately

if char == string[-1]:

Instead, use enumerate function, like this

for index, char in enumerate(input_string):
    if index + 1 == len(input_string):
        break

enumerate will give the current index and the actual item from the iterable, on every iteration. So, you can check if the current index + 1 is equal to the length of the string to make sure that you are really at the last position of the string.