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{ Sparse Arguments |
initial writing: 2001-03-01 |
The dyads { now supports sparse left arguments.
(It had long supported sparse right arguments.)
For example:
] d=: ?. 2 3 $ 7
0 5 3
3 1 0
] s=: $. d
0 1 | 5
0 2 | 3
1 0 | 3
1 1 | 1
] v=: 7 ?. 7
6 1 2 5 4 3 0
s{v
0 1 | 3
0 2 | 5
1 0 | 5
1 1 | 1
$.^:_1 s{v
6 3 5
5 1 6
d{v
6 3 5
5 1 6
(s{v) -: d{v
1
s{i.7 3
|non-unique sparse elements
| s {i.7 3
s{"(1) 0,. 10 20+/i.7
0 1 | 14
0 2 | 12
1 0 | 22
1 1 | 20
d{"(1) 0,. 10 20+/i.7
0 14 12
22 20 0
s{"(1) 10 20+/i.7
|non-unique sparse elements
| s {"(1)10 20+/i.7
j=: ?. 1000$2e9
s=: 1 j} 1 $. 2e9 ;0;0
$s
2000000000
$ s { 10 20
2000000000
(s { 10 20) -: 20 j} 1 $. 2e9;0;10
1