Function or operator to test list membership

[sbergman27]

I'm looking for a quick way to check to see if an integer is an element of a list. Maybe I'm just searching for the wrong terms in the Prime User Guide. But I haven't found a fast way to do it. Is "intersect" my best bet?

[Didier Lachieze]

You can use:
POS(list, element)

Returns the position of an element within a list. A value of 0 is returned if there is no occurrence of the specified element.

Example:
POS ({3,7,12,19},12) returns 3

[sbergman27]

Thank you.