Re: [Caml-list] Re: "ocaml_beginners"::[] string to list

[Issac Trotts <ijtrotts@ucdavis.edu>]

Brian Hurt wrote:

>On Mon, 17 Feb 2003, Issac Trotts wrote:
>
>  
>
>>Christian Schaller wrote:
>>
>>    
>>
>>>Hi everyone!
>>>
>>>I'm trying to find a built in function for converting a string to a list of
>>>characters, similar to SML's explode.  Is something like this available?
>>>
>>>Thank you!
>>>
>>>- Chris
>>>
>>>      
>>>
>># let explode s =
>>   let n = String.length s in
>>   let rec aux k = if k = n then [] else s.[k] :: aux (k+1) in
>>   aux 0;;
>>      val explode : string -> char list = <fun>
>># explode "foo";;
>>- : char list = ['f'; 'o'; 'o']
>>
>>    
>>
>
>let explode s = 
>    let n = String.length s in
>    let rec aux k accum = if k = n then (List.rev accum) 
>                          else aux (k+1) (s.[k] :: accum)
>    in
>    aux 0 []
>;;
>
>See previous discussion.
>
Good point: we want it to be tail-recursive.  
Just to clean up, and make it more efficient...

let explode s = 
    let rec aux k accum = if k = -1 then accum
                          else aux (k-1) (s.[k] :: accum)
    in
    aux (String.length s - 1) []
;;


Issac

>
>Brian
>
>
>
>  
>



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