HP Forums
Confused about indexing into lists... - Printable Version

+- HP Forums (https://www.hpmuseum.org/forum)
+-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html)
+--- Forum: HP Prime (/forum-5.html)
+--- Thread: Confused about indexing into lists... (/thread-9441.html)



Confused about indexing into lists... - webmasterpdx - 11-05-2017 01:36 AM

My understanding was that in CAS mode, lists should be indexed using square brackets to avoid confusion with function calls, so I tried the following....

L1:={1,2,3,4,5,6,7,8,9}

When in Home mode, I can type L1(3) or L1[3] and I'll get 3 back....correct...both braces work.

Now, go to CAS mode.

L1(3) works and returns 3...so next I tried the square brackets...

L1[3] gets converted to at(L1,2) and {1,2,3,4,5,6,7,8,9} gets returned??????

So, then I typed...

at(L1,2) and it returned at({1,2,3,4,5,6,7,8,9},2) ????

So, what am I doing wrong?


RE: Confused about indexing into lists... - Tim Wessman - 11-05-2017 02:17 AM

(11-05-2017 01:36 AM)webmasterpdx Wrote:  My understanding was that in CAS mode, lists should be indexed using square brackets to avoid confusion with function calls, so I tried the following...

Almost. Use () with all home variables and objects.


RE: Confused about indexing into lists... - webmasterpdx - 11-05-2017 03:08 AM

That's confusing. How does one know if a variable passed into a program is a CAS or Home variable?


RE: Confused about indexing into lists... - Tim Wessman - 11-05-2017 03:27 AM

So you're taking arbitrary input into your program and not checking type or what the user gave you before attempting to do something to it?


RE: Confused about indexing into lists... - webmasterpdx - 11-05-2017 03:57 AM

Hmm....if I pass in a home list to a cas function as a list, it gets converted to a cas list and can be addressed with []. So I guess that solves that problem.
It's still pretty confusing though (from the command line).

The other thing that really bugs me is if I am looking for a function that is a cas program, it should be accessible from the toolbox menu, under the USER submenu, like the home functions. It's pretty disconnected to have the cas ones under the variables-CAS-Programs submenu....