Hi. I faced a problem while excuting my code. But I get an error 'TypeError: can only concatenate str (not "int") to str' for the last pointer

Question

 lst = ['a', 'b', 'c', 'd', 'e', 'i', 'u', 'y', 'l', 'i']

 if(len(lst)%3==0):
     pointer = 0
     for i in lst:
         for j in range(pointer, pointer+3):
             print(lst[j])
             pointer += 1
 else:
    rem = 3
    pointer = 0
    for i in lst:
        for j in range(pointer, pointer+3):
            print(lst[j])
            pointer += 1
            rem -= 1
            if (pointer > rem):
                pointer = lst [0]
            print(lst[j])

I am not sure if I have a good approach or not, but I wanted my pointer to get to the first element of the list, if the number of elements is not divisible by 3.

Answer 1

When you say

pointer = lst[0]

the pointer variable will now be storing a string ( lst[0] should be the string 'a' from your list). So when your code later runs into the line:

pointer += 1

you are now attempting to add the string 'a' to the integer 1 . That's where the type error comes from. You can either "add" two numbers, or "concatenate" two strings. You can't combine a string and an integer without explicitly converting one into the other.