Parameter List
Syntax
ISLOGICAL(value)
value
The value to test for logical type. For example: TRUE, FALSE, A1, 1=1, or any expression that might return a logical value.
More details
ISLOGICAL specifically tests for logical values TRUE and FALSE. It returns TRUE only for these boolean values and FALSE for everything else, including text representations of "TRUE" or "FALSE", numbers like 1 or 0, and any other data types.