RE: [External] : Swapping characters in a word inside elisp code

[uzibalqa]

------- Original Message -------
On Saturday, July 29th, 2023 at 8:32 AM, Drew Adams <drew.adams@oracle.com> 
wrote:


> > I have a word and want to swap characters at position i with position j.
> > 
> > What would be a good way to do this ? Would I need to change structure
> > (to array, vector or some other thing) ?
> 
> 
> (Homework?)
> 
> Depends what you mean by swap chars in a word.
> And whether your word is represented by a string,
> a vector, a list... And how you want the result:
> in a separate string, vector,... or in the same
> one, modified.

I have a word and want to generate permutations of it.
And I need the ability to swap two characters at positions
i and j in word.

Just a toy project that does scrabble.

 
> (Again, you don't make clear what you want.)
> 
> Here's one way to swap chars in a string
> destructively:
> 
> (defun cswap (string p q)
> "Swap chars in STRING at positions P and Q.
> This is a destructive operation."
> (aset string p (prog1 (aref string q)
> (aset string q (aref string p))))
> string)
> 
> (setq s1 "123456789")
> (cswap s1 3 5) ; s1 = "123654789"
> ; ^ ^
> 
> `prog1' is often used to swap things.
> A more typical use is swapping values
> of two variables:
> 
> (setq start (prog1 end (setq end start)))