50g System RPL list processing

[Gilles]

(11-01-2014 02:48 PM)Claudio L. Wrote:  

(10-31-2014 10:06 PM)Gilles Wrote:  Note that the 50G use sometimes a '?' value (something like unknown or undetermined algebraic... For examplle lim (x->+oo,SIN(X)) -> ?
Could be interesting in some cases. A kind of NIL for algebraic

(...) I think this is more generic, but still doesn't cover all cases, since it won't work for objects that are not accepted inside symbolics, like strings.
'?'+"HELLO" will give an error.

Hi Claudio :

? "Hello" + gives "'?'Hello"
'?' works both in numeric and exact mode. (Oh I see ! :It works only with FLAG 3 OFF )

And you can do


«
'?'
IF '?' SAME THEN "Undeterminded" END
»

(but == does'nt work)

['?' 1 2 3 ]
{'?' 1 2 4 }

are OK

{'?' 1 2 3 } ΣLIST gives '?'
which seems correct

[[1 2][3'?']] INV gives [[? ?][? ?]]
in exact and approx mode (with flag 3)