string - Python - Extracting a substring using a for loop instead of Split method or any other means -

this question exact duplicate of:

• splitting input 2 for-loop 2 answers

i'm taking online python course poses problem programmer extract substring using loop. there similar question asked year ago, didn't answered.

so problem reads:

write program takes single input line of form «number1»+«number2», both of these represent positive integers, , outputs sum of 2 numbers. example on input 5+12 output should 17.

the first hint given is

use loop find + in string, extract substrings before , after +.

this attempt, know wrong because there no position in loop equals '+'. how find position '+' in string "5+12"?

s = input() s_len = len(s) position in range (0,s_len):    if position == '+':       print(position[0,s_len]) 

**spoiler alert - edit show csc waterloo course takers answer

s = input() s_len = len(s) position in range (0,s_len):    if s[position] == '+':       number1 = int(s[0:position])       number2 = int(s[position:s_len]) sum = number1 + number2 print(sum) 

use enumerate, if want using loop:

s = input() position, character in enumerate(s):    if character == '+':       print(position)       break  # break out of loop once character found 

enumerate returns both index , item iterable/iterator.

>>> list(enumerate("foobar")) [(0, 'f'), (1, 'o'), (2, 'o'), (3, 'b'), (4, 'a'), (5, 'r')] 

working version of solution:

s = input() s_len = len(s) position in range(0, s_len):    if s[position] == '+':        #use indexing fetch items string.       print(position)