I'm trying to write a module that searches for a key string in a target string and outputs the starting points of any matches. I can write an iterative module that achieves this, but I'm attempting to do it with recursion (the tutorial I'm using deals with recursion and iteration in this lesson, so I figure I should try both) and running into some trouble.
def substringmatchrecursive(target, key):
"""returns a tuple of the starting points of matches of the key string in the target string using a recursive function"""
from string import find
position = find(target, key) #position of the match
answer=() #will be outputted
if position == -1:
return 'No match'
else:
while position != 1:
answer = answer + (position, )
position = substringmatchrecursive(target[position+1: ], key)
return answer
loading the module and entering
substringmatchrecursive("fjdkakfjdslkfajfksja", "a")
which should give me a tuple of length 3, instead gives me an error
Traceback (most recent call last):
.....
position = substringmatchrecursive(target[position+1: ], key)
TypeError: cannot concatenate 'str' and 'int' objects
I'd assume that find() would output an integer, so position+1 should work. What is going on here?
