# xf:string-length

Counts the length of $string-var.

If the value of $string-var is the empty sequence, the empty sequence is returned. The empty sequence is a sequence containing zero items (), which is similar to null in SQL.

### Signatures

xf:string-length(xs:string? $string-var) —> xs:integer?

### Arguments

Data Type | Argument | Description
--- | --- | ---
xs:string? | $string-var | Represents the string to count.

### Returns

Returns an integer equal to the length of the $string-var.

### Examples

#### Simple

Invoking string-length("moo cow") returns the integer 7, as shown in the following example query:

    <result>{xf:string-length("moo cow")}</result>

The preceding query generates the following result:

    <result>7</result>

#### Pass in Null

Invoking string-length(()) returns the null string as shown in the following example query:

    <result>{xf:string-length(())}</result>

Note: The string: () is the empty sequence (similar to a SQL null) which is a sequence containing zero items.

The preceding query generates the following result:

    <result/>

Related Topics

W3C string-length function description.