Re: Rotate sequence

From	"WJ" <w_a_x_man@yahoo.com>
Newsgroups	comp.lang.forth
Subject	Re: Rotate sequence
Date	2013-07-07 03:20 +0000
Organization	A noiseless patient Spider
Message-ID	<krampi$ocr$1@dont-email.me> (permalink)
References	<khbfcu0gki@enews4.newsguy.com>

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WJ wrote:

> P19 (**) Rotate a list N places to the left.
>     Examples:
>     * (rotate '(a b c d e f g h) 3)
>     (D E F G H A B C)
>    
>     * (rotate '(a b c d e f g h) -2)
>     (G H A B C D E F)
> 
> Factor:
> 
> : rotate ( seq n -- seq )
>   dup 0 < [ abs cut* ] [ cut ] if
>   swap append
> ;
> 
> { "a" "b" "c" "d" "e" } 2 rotate .
> { "c" "d" "e" "a" "b" }
> { "a" "b" "c" "d" "e" } -2 rotate .
> { "d" "e" "a" "b" "c" }

Julia:

julia> circshift( [2,3,4], 1)
3-element Int32 Array:
 4
 2
 3

julia> circshift( [2,3,4], -1)
3-element Int32 Array:
 3
 4
 2

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Rotate sequence "WJ" <w_a_x_man@yahoo.com> - 2013-03-08 01:37 +0000
  Re: Rotate sequence "WJ" <w_a_x_man@yahoo.com> - 2013-07-07 03:20 +0000

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