Hello Ric;
This thread seems to go around a J 'gotcha', the first I can recall
which works this way, as opposed to things like #.^:_1 which work as you
would expect them to, if you repressed your expectation of an error.
M
6 5 9 2
4 9 0 7
0 4 6 8
3 8 1 2
_((I. 0=,M)"_)}M
6 5 9 2
4 9 _ 7
_ 4 6 8
3 8 1 2
_(I. 0=,M)}M
|index error
| _ (I.0=,M)}M
Indices suggested by u in u}y are allowed to be in terms of the ravelled
noun y, but those suggested by m in m}y cannot be.
Fortunately,
x m"_ }v
is a valid workaround. NB. My J epiphany of the day.
Sherlock, Ric wrote:
---Alex Rufon wrote:
What I want to do is to replace all zero in the matrix with infinity.
]M=: 4 [EMAIL PROTECTED]
6 5 9 2
4 9 0 7
0 4 6 8
3 8 1 2
amendZeros=: _&(([: I. 0 = ,@])})
amendZeros M
6 5 9 2
4 9 _ 7
_ 4 6 8
3 8 1 2
Check out Chapter 6.3.3 Linear Indices in Learning J
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
--
------------------------------------------------------------------------
|\/| Randy A MacDonald | APL: If you can say it, it's done.. (ram)
|/\| ramacd <at> nbnet.nb.ca |
|\ | | The only real problem with APL is that
BSc(Math) UNBF'83 | it is "still ahead of its time."
Sapere Aude | - Morten Kromberg
Natural Born APL'er |
-----------------------------------------------------(INTP)----{ gnat }-
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
