IS Functions
This section describes the nine worksheet functions used for testing the type of a value or 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 reference to an empty cell; otherwise it returns FALSE.
Syntax
ISBLANK(value)
ISERR(value)
ISERROR(value)
ISLOGICAL(value)
ISNA(value)
ISNONTEXT(value)
ISNUMBER(value)
ISREF(value)
ISTEXT(value)
Value is the value you want tested. Value can be a blank (empty cell), error, logical, text, number, or reference value, or a name referring to any of these, that you want to test.
Function |
Returns TRUE if |
ISBLANK |
Value refers to an empty cell. |
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 cell.) |
ISNUMBER |
Value refers to a number. |
ISREF |
Value refers to a reference. |
ISTEXT |
Value refers to text. |
Remarks
- The value arguments to 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).
Examples
ISLOGICAL(TRUE)
equals TRUE
ISLOGICAL("TRUE")
equals FALSE
ISNUMBER(4)
equals TRUE
Suppose C1:C5 on a worksheet of gold prices in different regions shows the following text values, number values, and error values: "Gold", "Region1", #REF!, $330.92, #N/A, respectively.
ISBLANK(C1)
equals FALSE
ISERROR(C3)
equals TRUE
ISNA(C3)
equals FALSE
ISNA(C5)
equals TRUE
ISERR(C5)
equals FALSE
ISNUMBER(C4)
equals TRUE (if the $330.92 was entered as a number and not as text)
ISREF(Region1)
equals TRUE (if Region1 is defined as a range name)
ISTEXT(C2)
equals TRUE (if Region1 is formatted as text)
On another worksheet, suppose you want to calculate the average of the range A1:A4, but you can't be sure that the cells contain numbers. The formula AVERAGE(A1:A4) returns the #DIV/0! error value if A1:A4 does not contain any numbers. To allow for this case, you can use the following formula to locate potential errors:
IF(ISERROR(AVERAGE(A1:A4)),"No Numbers",AVERAGE(A1:A4))