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Groups > comp.lang.forth > #20174

Re: Filtering

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On Sat, 02 Mar 2013 02:48:43 -0500, WJ <w_a_x_man@yahoo.com> wrote:

> Given a sequence of numbers, keep those that are odd and
> multiply them by 100.
>
> Factor:
>
>
> USE: sequences.extras
>
> { 1 1 2 3 5 8 13 21 } [ odd? ] [ 100 * ] filter-map
> { 100 100 300 500 1300 2100 }


Parable:

[ #1 #1 #2 #3 #5 #8 #13 #21 ] array-from-quote
[ odd? ] array-filter [ #10 * ] array-map


Retro:

needs array'
needs math'
with| array' math' |

create results 100 allot
new{ 1 1 2 3 5 8 13 21 }
[ dup odd? [ 100 * @results results + 1+ ! results ++ ] ifTrue ] apply
results display


-- crc

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Filtering "WJ" <w_a_x_man@yahoo.com> - 2013-03-02 07:48 +0000
  Re: Filtering mhx@iae.nl (Marcel Hendrix) - 2013-03-02 11:17 +0200
  Re: Filtering "Charles Childers" <crc@retroforth.org> - 2013-03-02 11:18 -0500
    Re: Filtering "A. K." <akk@nospam.org> - 2013-03-02 17:55 +0100
      Re: Filtering Marc Olschok <nobody@nowhere.invalid> - 2013-03-03 22:11 +0000

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