Python - Intersectiing strings

Question

Trying to write a for function that takes two strings and returns the characters that intersect in the order that they appear in the first string.

Here\'s what I tri

Answer 1

Check for occurances the other way around to get the order under control, and don't emit characters you've already emitted:

def strIntersection(s1, s2):
  out = ""
  for c in s1:
    if c in s2 and not c in out:
      out += c
  return out

Sure you could re-write it to be a list comprehension, but I find this easier to understand.

For your test data, we get:

>>> strIntersection('asdfasdfasfd' , 'qazwsxedc')
'asd'