How does Excel use the ISNA function to judge data?

How does Excel use the ISNA function to judge data?

The meaning of ISNA function

To determine whether a value is #n/a, return true correctly, or false.

The grammatical format of the ISNA function

1. Syntax format of ISNA function

=isna (value)

Third, the ISNA function case column

1, as shown in the figure, enter the formula =isna (A1), return True.

2. ISNA functions are often used in conjunction with other functions. As shown in the figure, the value is not found in the process of using the VLOOKUP function, and an error value #n/a occurs. What to do now.

3, then use if and VLOOKUP function to get rid of the error value #n/a. Because you do not remove the error value N/A, then use the sum and other functions will be wrong, then the error value #n/a removed.