Please help with function

Hello,

I would like to write a lisp function that reads a string and inserts a 
space after every character: "String" -> "S t r i n g ".
I have a little lisp experience, but don't know which functions to use to 
modify the string.

Could you just give me some hints, where I have to look/ which functions I 
can use ? I would like to find out the "rest" myself to learn a bit...

TIA,

Markus Grunwald
Softwareentwicklung

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