Francois Maltey <[EMAIL PROTECTED]> writes:
> With axiom I only find this multi-line command :
> L := reduce
> (append,
> [reduce
> (append,
> [reduce
> (append,
> [[matrix [[a,b,15-a-b],[c,d,15-c-d],[15-a-c,15-b-d,15-a-d]]
> for a in 1..9] for b in 1..9]) for c in 1..9]) for d in 1..9]) ;
you can shorten this in two different ways:
* reduce(append, l) is the same as concat l, thus, you can write
L := concat [concat [concat [[matrix [[a,b,15-a-b],_
[c,d,15-c-d],_
[15-a-c,15-b-d,15-a-d]] _
for a in 1..9]_
for b in 1..9]_
for c in 1..9] _
for d in 1..9]
* you could first generate all Cartesian products with
L := concat [concat [concat [[[a,b,c,d] _
for a in 1..9] _
for b in 1..9] _
for c in 1..9] _
for d in 1..9]
and then loop over them:
[eval(matrix [[a,b,15-a-b],[c,d,15-c-d],[15-a-c,15-b-d,15-a-d]], [a,b,c,d], l)
for l in L]
> a train of for creates only one zip-list.
Yes, and that's something very useful! For example
[f(l) for l in L for i in 1..4]
only uses the first for elements in L, or
[f(l, i) for l in L for i in 1..]
is in my opinion much better to read then
[f(L.i, i) for i in 1..#L]
Martin
_______________________________________________
Axiom-developer mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/axiom-developer
