In a formula, how to check if a variable belongs to a set of values

A common need when doing formulas is to check whether a variable (generally, a column) belongs to a set of values.

For example, you may want to check if mycolumn has value 1, 2 or 3. To do that in a formula, use the arrayContains function:

arrayContains([1,2,3], mycolumn)

In other words, instead of checking if “mycolumn is in [1,2,3]”, you check if “[1,2,3] contains mycolumn”.

It is useful to remember the usual formula rules to refer the values of columns:

For example, to do the same in a column named my column (note the space), you would use:

arrayContains(["a", "b", "c"], strval("my column"))