Using the Excel ISLOGICAL Function

Summary
The Excel ISLOGICAL function will return TRUE when a cell contains the logical values TRUE or FALSE. The function returns FALSE for all cells containing other values, including empty cells.Syntax
=ISLOGICAL (Value)Syntax Breakdown
ValueRequired. A value that will be tested as logical (either TRUE or FALSE). Typically supplied as a cell address.
Usage Notes
ISLOGICAL checks if a cell contains either logical value TRUE or FALSE. The function returns TRUE if a logical value is found and FALSE in all other cases.The ISLOGICAL function does not evaluate 1 and 0 (zero) as TRUE and FALSE.