topic Re: How to check if a list contains any values from another list? in Discussions

How to check if a list contains any values from another list?

miguello — Tue, 28 Jan 2025 04:04:40 GMT

Is there an elegant one-liner for that rather than iterate through the second list using Contains() function?

Re: How to check if a list contains any values from another list?

miguello — Tue, 28 Jan 2025 04:26:55 GMT

Not one-liner, but more elegant than a loop:

A = {1, 2, 3, 4, 5};
B = {3, 6, 7};
check = Associative Array(A);
check << Intersect(Associative Array(B));
N Items(check);

Re: How to check if a list contains any values from another list?

txnelson — Tue, 28 Jan 2025 04:27:16 GMT

You can loop through one of the lists and use Contains() to see if the specific list item is found anywhere in the other list.

Or, you can convert both of the lists into separate Associative Arrays and then check for the Intersect between the two arrays.

Names Default To Here( 1 );

listA = {"a", "b", "c"};

listB = {"d", "c", "f"};

inBothList = {};

For Each( {member}, listA,
	If( Contains( listB, member ),
		Insert Into( inBothList, member )
	)
);

Show( inBothList );

arrayA = Associative Array( listA );
arrayB = Associative Array( listB );

arrayA << intersect( ArrayB);

show( arrayA );

Re: How to check if a list contains any values from another list?

jthi — Tue, 28 Jan 2025 09:54:19 GMT

I usually use either For Each + Break or Associative Arrays but there are many different methods where you can use functions a bit "incorrectly" such as Transform Each ("one-liner" such as this are usually horrible ideas (in my opinion) as they tend to be difficult to read)

Names Default To Here( 1 );

A = {1, 2, 3, 4, 5};
B = {3, 6, 7};

r = Eval(Transform Each({item}, A, Output("Expression", "Any"), Contains(B, item)));

It also depends on what you are comparing: strings, integers, floats, lists, ... as JMP lists can basically contain anything.