# Write a function that takes a string and a substring
# and removes all instances of the substring,
# returning that new resultant string.
# You may assume the substring is of size 1
#
# You may not use any built-in functions/methods
# besides len() and .append().
# Specifically, you may NOT use the replace() method.


def remove_string(string, sub):
    result = ""

    for index in range(len(string)):
        if (string[index] != sub):
            result += string[index]

    return result


print(remove_string("introduction to python", "n"))

# what if substring is longer -- says 2, 3, .. characters long
# how should we modify the code