List indexing problems

[Didier Lachieze]

(10-01-2016 05:16 AM)TravisE Wrote:  But:

Code:


{1,2,3}(1);   // → {1,2,3}
{1,2,3}[1];   // → {[1],[2],[3]} (?!)
{"a","b","c"}(2);   // Error: Bad argument type

Here the issue comes from the implicit multiplication as {1,2,3}(1) is interpreted as {1,2,3}*(1) and not as "take the first element of {1,2,3}".

(10-01-2016 05:16 AM)TravisE Wrote:  And, most importantly to me at the moment:

Code:


LOCAL a:={{"A",1,2},{"B",3,4}};
EXECON("&1(1)",a);   // Expected: retrieve a list of first elements in each sublist
   // Actual result: “Error: Bad argument type”
   // Same result if [ ] are used instead of ( )

Someone please tell me there's an alternative function or syntax for list indexing that works reliably.…

Instead of EXECON try with :

Code:

MAKELIST(a(I,1),I,1,SIZE(a));