=ISNA(value)
=ISNA(B2)
This returns TRUE if B2 contains an #N/A error. This is because ISNA is used to test for #N/A errors in a cell.
=ISNA(A1)
If you want to test for an error in a cell that contains a formula, you can use the ISNA function. For example, if you entered =B2+C2 in cell A1, you can use the ISNA function to test for any #N/A errors in the result. You would enter the preceding formula in another cell, which would return TRUE if A1 contains an #N/A error.
=ISNA(A1:A10)
The ISNA function can also be used to test for #N/A errors in an array formula. For example, if you have a range of cells that contains a formula, you can use the ISNA function to test for #N/A errors in the entire range. The formula would return TRUE if any of the cells in the range contain an #N/A error.
=ISNA(A1)
You can also use the ISNA function to test for #N/A errors in a lookup function. For example, if you have a VLOOKUP formula in cell A1, you can use the ISNA function to test for any #N/A errors in the result. This would return TRUE if A1 contains an #N/A error.
The ISNA function is an information function used to check if a cell contains an #N/A! error, which indicates that the data is not available. It can be used with the IF function to test the cell and display a customized message.