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replace_all

Language/Type: Python recursion string return

Write a recursive function named replace_all that accepts three parameters: a string s, a from, and a to as parameters, and returns a new string that is the same as s but with any occurrences of from changed to to. For example, the call of replace_all("crazy raccoons", 'c', 'k') should return "krazy rakkoons" and the call of replace_all("BANANA", 'A', 'O') should return "BONONO".

Your function is case-sensitive if the character from is, for example, a lowercase 'f', your function should not replace uppercase 'F' characters. In other words, you should not need to write code to handle case issues in this problem.

Constraints:

  • Do not use any loops you must use recursion.
  • Do not declare any global variables.
  • Do not call any of the following string member functions: find, rfind, index_of, contains, replace, split. (The poof this problem is to solve it recursively do not use a library function to get around recursion.)
  • Do not use any auxiliary data structures like list, dict, set, etc.
  • You can declare as many primitive variables like ints as you like, as well as strings.
  • You are allowed to define other "helper" functions if you like they are subject to these same constraints.
Function: Write a Python function as described, not a complete program.

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