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+--- Thread: How to remove an item from a list? [SOLVED] (/thread-7087.html)
How to remove an item from a list? [SOLVED] - cclinus - 10-22-2016 07:52 AM
Hi,
This is my list: {0, {0,1,2},{0,1,2}}
I want to remove the last item {0,1,2} from the list but keep the first two items.
How?
end result should be {0, {0,1,2}}
I had read some command such as DELCOL(only work with matrix), remove(can not keep one {0,1,2} in the list.
Thanks!
RE: How to remove an item from a list? - Didier Lachieze - 10-22-2016 09:07 AM
I don't think there is a built-in command to remove an item from a list.
Here is a small program to do it :
Code:
EXPORT Remove(l,n) //remove item n from list l
BEGIN
LOCAL s:=SIZE(l);
CASE
IF n==1 THEN l({2,s}) END;
IF n==s THEN l({1,s-1}) END;
IF n>1 AND n<s THEN CONCAT(l({1,n-1}),l({n+1,s})) END;
DEFAULT l END;
END;RE: How to remove an item from a list? - StephenG1CMZ - 10-22-2016 09:28 AM
http://www.hpmuseum.org/forum/thread-7001.html
is also a useful library of list-handling procedures in the software library.
Suggested enhancement to the syntax:
To remove an item from the end of the list, the simplest and most obvious syntax would be
SIZE(Let):=SIZE(Let)-1
But SIZE(Let):=
Is not currently supported.
RE: How to remove an item from a list? - DrD - 10-22-2016 10:02 AM
You could use this syntax:
{0, {0,1,2},{0,1,2}}; // Original list
SUB({0, {0,1,2},{0,1,2}},1,2); // End result desired ==> {0, {0,1,2}}
-Dale-
RE: How to remove an item from a list? - cclinus - 10-22-2016 11:23 AM
Hi Dale,
Thanks! But it is partially work.
If I assign a:={0,{0,1,2},{0,1,2}}
Then SUB(a,1,2)
IN Home mode , it is ok.
But if in CAS mode, It display Error: Invalid dimension.
How to make it work in CAS mode?
FINALLY, I find a way to make it work in CAS mode.
EXPR("SUB(a,1,2)");
TOO BAD, it seems doesn't work in cas program when "a" is local variable.
Thanks!
RE: How to remove an item from a list? - CH3791 - 10-22-2016 11:53 AM
Perhaps you can also consider a CAS program?
http://www.hpmuseum.org/forum/thread-3590.html
If you can always access/mostly use CAS, I think they are a much better choice than normal programs. It's more straightforward to program and it accepts your input with all the symbolic representation (ie doesn't convert things like pi to decimal).
RE: How to remove an item from a list? - DrD - 10-22-2016 01:15 PM
(10-22-2016 11:23 AM)cclinus Wrote: If I assign a:={0,{0,1,2},{0,1,2}}
Then SUB(a,1,2)
IN Home mode , it is ok.
But if in CAS mode, It display Error: Invalid dimension.
How to make it work in CAS mode?
Try using lower case sub instead of SUB, in CAS:
sub(a,1,2); ==> end result in CAS.
Also, you might like to use list variables L0..L9.
-Dale-
RE: How to remove an item from a list? - cclinus - 10-23-2016 06:28 AM
Hi Dale,
Thanks! It works.
sub(a,1,2); //OK
Regards,