Notice
;/ 2 4 6 8 10 + recf i. 2 2 NB. ;/ is added for space reasons
+---+---+---+-----+-----+-----+
|0 1|2 3|6 7|12 13|20 21|30 31|
|2 3|4 5|8 9|14 15|22 23|32 33|
+---+---+---+-----+-----+-----+
whereas Phillips' (f/"1 @ ,.) does not meet the specs:
(<"_1[2 4 6 8 10) (+&.>/"1 @ ,.) <i. 2 2
+---+---+---+-----+-----+
|2 3|4 5|6 7| 8 9|10 11|
|4 5|6 7|8 9|10 11|12 13|
+---+---+---+-----+-----+
I would suggest
a ([:> [: f&.>/\.&.|. <@],<"[EMAIL PROTECTED]) m
so
;/ 2 4 6 8 10 ([:> [:+&.>/\.&.|. <@],<"[EMAIL PROTECTED]) i. 2 2 NB. ;/
is
extra
+---+---+---+-----+-----+-----+
|0 1|2 3|6 7|12 13|20 21|30 31|
|2 3|4 5|8 9|14 15|22 23|32 33|
+---+---+---+-----+-----+-----+
R.E. Boss
-----Oorspronkelijk bericht-----
Van: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Namens Steven Phillips
Verzonden: vrijdag 12 mei 2006 5:05
Aan: Programming forum
Onderwerp: Re: [Jprogramming] 2 f 3 f 4 f m
Assuming m and the items of a are boxed, then
a (f/"1 @ ,.) m
where f has the form (g each).
Steve
Fraser Jackson wrote:
> What is the simplest way of expressing the very commonly needed
> form of which the subject line is an example:
>
> a3 f a2 f a1 f m
>
> a list of items a =. a1, a2, a3, ... applied successively with a
> function f and a right argument m of a different shape or even of a
> different type. This occurs with any sequential updating process.
>
> The intermediate results are often of interest themselves. recf does
> what I want, but is there a neater way?
>
> recf=: 1 : 0
> :
> s =. y
> r =. ,:y
> for_i.
> i. # x
> do. s =. (i{x) u s
> r =. r,s
> end.
> r
> )
>
> 2 4 6 8 10 + recf i. 2 2
>
>
>
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>
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