Remove First and Last Character Part Two

Description:

This is a spin off of my first kata.

You are given a string containing a sequence of character sequences separated by commas.

Write a function which returns a new string containing the same character sequences except the first and the last ones but this time separated by spaces.

If the input string is empty or the removal of the first and last items would cause the resulting string to be empty, return an empty value (represented as a generic value NULL in the examples below).

Examples

"1,2,3"      =>  "2"
"1,2,3,4"    =>  "2 3"
"1,2,3,4,5"  =>  "2 3 4"

""     =>  NULL
"1"    =>  NULL
"1,2"  =>  NULL

 

 

Solution:

1. Split the string into an array and exclude elements on the edges.
2. It returns with spaces between elements.
3. If there is no value to return, it returns None.

 

def array(string):
  return " ".join(string.split(",")[1:-1]) or None