This article describes the eight functions used for testing the type of a value or column reference. Each of these functions, referred to collectively as the IS functions, checks the type of value and returns TRUE or FALSE depending on the outcome. For example, the ISBLANK function returns the logical value TRUE if value is a column reference that is empty; otherwise it returns FALSE.

Syntax

ISBLANK(value)

ISERR(value)

ISERROR(value)

ISLOGICAL(value)

ISNA(value)

ISNONTEXT(value)

ISNUMBER(value)

ISTEXT(value)

Value     is the value you want tested. Value can be blank, error, logical, text, number, or column reference.

Function

Returns TRUE if

ISBLANK

Value refers to an empty column reference.

ISERR

Value refers to any error value except #N/A.

ISERROR

Value refers to any error value (#N/A, #VALUE!, #REF!, #DIV/0!, #NUM!, #NAME?, or #NULL!).

ISLOGICAL

Value refers to a logical value.

ISNA

Value refers to the #N/A (value not available) error value.

ISNONTEXT

Value refers to any item that is not text. (Note that this function returns TRUE if value refers to a blank column reference.)

ISNUMBER

Value refers to a number.

ISTEXT

Value refers to text.

Remarks

• The value arguments of the IS functions are not converted. For example, in most other functions where a number is required, the text value "19" is converted to the number 19. However, in the formula ISNUMBER("19"), "19" is not converted from a text value, and the ISNUMBER function returns FALSE.

• The IS functions are useful in formulas for testing the outcome of a calculation. When combined with the IF function, they provide a method for locating errors in formulas (see the following examples).

Example set 1

Formula

Description (Result)

=ISLOGICAL(TRUE)

Checks whether TRUE is a logical value (Yes)

=ISLOGICAL("TRUE")

Checks whether "TRUE" is a logical value (No)

=ISNUMBER(4)

Checks whether 4 is a number (Yes)

Example set 2

Col1

Formula

Description (Result)

Gold

=ISBLANK([Col1])

Checks whether the value in Col1 is blank (No)

#REF!

=ISERROR([Col1])

Checks whether #the value in Col1 is an error (Yes)

#REF!

=ISNA([Col1])

Checks whether the value in Col1 is the #N/A error (No)

#N/A

=ISNA([Col1])

Checks whether the value in Col1is the #N/A error (Yes)

#N/A

=ISERR([Col1])

Checks whether the value in Col1 is an error (No)

330.92

=ISNUMBER([Col1])

Checks whether the value in Col1 is a number (Yes)

Region1

=ISTEXT([Col1])

Checks whether the value in Col1 is text (Yes)