Ack, posted the next-to-last version. Here's the correct one:
replaceZeroes =: (;@:;@:([([:<(((_1 1 (] i.&0)}"0 1 ])`])@.(# =
i.&0)))\]))^:_
Then
_2 replaceZeroes 0 0
_1 _1 _1 1 1 _1 1 1
...which is the desired result. The left argument determines how many
elements there are in a sub-list.
Still, it looks like your code is (far) better than mine. I wasn't
familiar with catalogue before this, but it fits perfectly here.
thanks!
Geoff
On Mar 9, 2008, at 3:15 PM, R.E. Boss wrote:
replaceZeroes 0 0
_1 _1 1 _1 _1 _1 1 1 _1 1 1 _1 _1 1 1 1
;<@,@:{"1 (<1 _1)(0([EMAIL PROTECTED] <@#: I.@,@:=) M)}<"0 M=:0 0
1 1
1 _1
_1 1
_1 _1
Apparently replaceZeroes generates too much.
R.E. Boss
-----Oorspronkelijk bericht-----
Van: [EMAIL PROTECTED] [mailto:programming-
[EMAIL PROTECTED] Namens R.E. Boss
Verzonden: zondag 9 maart 2008 23:11
Aan: 'Programming forum'
Onderwerp: RE: [Jprogramming] Turning 0 into _1 1 in a list
Oops, last one should be
;<@,@:{"1 (<1 _1)(0([EMAIL PROTECTED] <@#: I.@,@:=) M)}<"0 M
1 _1 1 1
1 _1 _1 1
1 1 _1 1
1 1 1 _1
1 1 _1 _1
_1 1 1 _1
_1 1 _1 _1
R.E. Boss
-----Oorspronkelijk bericht-----
Van: [EMAIL PROTECTED] [mailto:programming-
[EMAIL PROTECTED] Namens R.E. Boss
Verzonden: zondag 9 maart 2008 22:57
Aan: 'Programming forum'
Onderwerp: RE: [Jprogramming] Turning 0 into _1 1 in a list
[M=:1 _1 0 1,1 1 _1 1,:0 1 0 _1
1 _1 0 1
1 1 _1 1
0 1 0 _1
0([EMAIL PROTECTED] <@#: I.@,@:=) M
+---+---+---+
|0 2|2 0|2 2|
+---+---+---+
NB. coordinates of zeroes
(<1 _1)(0([EMAIL PROTECTED] <@#: I.@,@:=) M)}<"0 M
+----+--+----+--+
|1 |_1|1 _1|1 |
+----+--+----+--+
|1 |1 |_1 |1 |
+----+--+----+--+
|1 _1|1 |1 _1|_1|
+----+--+----+--+
NB. replace boxed zeroes by 1 _1
<@{"1 (<1 _1)(0([EMAIL PROTECTED] <@#: I.@,@:=) M)}<"0 M
+--------------------+----------+----------------------+
|+--------+---------+|+--------+|+---------+----------+|
||1 _1 1 1|1 _1 _1 1|||1 1 _1 1|||1 1 1 _1 |1 1 _1 _1 ||
|+--------+---------+|+--------+|+---------+----------+|
| | ||_1 1 1 _1|_1 1 _1 _1||
| | |+---------+----------+|
+--------------------+----------+----------------------+
NB. use catalogue to make all combinations
,;<@{"1 (<1 _1)(0([EMAIL PROTECTED] <@#: I.@,@:=) M)}<"0 M
1 _1 1 1
1 _1 _1 1
1 1 _1 1
1 1 _1 1
1 1 1 _1
1 1 _1 _1
_1 1 1 _1
_1 1 _1 _1
replaceZeroes M
1 _1 _1 1 1 _1 1 1 1 1 _1 1 _1 1 _1 _1 _1 1 1 _1 1 1 _1 _1 1 1 1 _1
R.E. Boss
-----Oorspronkelijk bericht-----
Van: [EMAIL PROTECTED] [mailto:programming-
[EMAIL PROTECTED] Namens Geoff Canyon
Verzonden: zondag 9 maart 2008 21:59
Aan: Programming forum
Onderwerp: Re: [Jprogramming] Turning 0 into _1 1 in a list
I think the eventual solution I came up with was somewhat similar
to
this. Here's my solution:
replaceZeroes =: (;@:;@:(_4([:<(((_1 1 (] i.&0)}"0 1 ])`])@.(# =
i.&0)))\]))^:_
I spent some time trying to figure out how to apply the replacement
repeatedly before boxing and then unbox at the end, to minimize
boxing/
unboxing, but I couldn't get that to work. So in the above, the
boxing/
unboxing happens for each replacement. This isn't so bad in my
particular case since no list has more than three zeroes in it.
If the
lists had many zeroes, the whole thing would come apart, since I'm
starting with 512 lists of 27 elements, so a bunch of zeroes would
quickly result in millions of lists. As it is, I end up with less
than
a thousand.
Still I wonder that there seems to be no way to avoid boxing/
unboxing?
If I have a list and I want to transform that list, with the
subsets I
take potentially changing in length, I can't do that without boxes?
Say I have a list like this: 1 2 3 4 5 6 7 8
And I want the result to be a list that a duplicate for each
prime in
the list:
1 2 2 3 3 4 5 5 6 7 7 8
Are boxes the only/best way?
regards,
Geoff
On Mar 4, 2008, at 5:17 AM, Raul Miller wrote:
I have some comments in addition to R.E.Boss's comments
(and using his M)
M=:1 _1 0 1,1 1 _1 1,:0 1 0 _1
A simple approach to supressing fill uses box (<) followed
by raze (;). In other words:
<@(_1 1 (] i.&0)}"0 1 ])`<@.(# = i.&0)"1 M
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