TypeError while looping through argv (Python)

Question

Trying to iterate through command line argument to check if each of the chars inside the string is an alphabet.

TypeError: string indices must be integers

import sys

k = sys.argv[1]

if len(sys.argv) != 2:
    print("Error.")
    return 1
else:
    for i in k:
        if k[i].isalpha() == False:
            return 1
            print("Error.")

Answer 1

Change the if statement inside the else statement to if i.isalpha() == False:

This is because the for loop iterates through the values of k and sets the variable i equal to the k[i]

If you would like to have the for loop set I to the indexes instead, the for loop must read as such:

for i in range(len(k)):