Design

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starts-with

The starts-with function in XQuery is used to determine whether a string begins with a specified substring. This function is particularly useful for string validation and prefix matching tasks.

Syntax

fn:starts-with(arg1, arg2, collation)

The following table describes the argument for this command:

Argument	Required/Optional	Description
arg1	Required	The main string to be checked. This is the string you want to determine if it starts with $arg2 . If it is an empty sequence ( () ), it is treated as an empty string.
arg2	Required	The substring to check for at the start of $arg1 . If this argument is an empty sequence, it is treated as an empty string.
collation	Optional	A URI that specifies the collation to be used for string comparison. Collations are sets of rules for comparing characters in strings. If this parameter is omitted, the default collation is used.

Return Value

Returns a boolean indicating whether or not the value of

$arg1

starts with a sequence of collation units that provides a minimal match to the collation units of

$arg2

according to the collation that is used.

Returns

true

if the main string

$arg1

starts with the substring

$arg2

Returns

false

if it does not.

Examples

The following table lists some sample values and return values:

SAMPLE FUNCTION	OUTPUT
fn:starts-with('query', 'que')	true
fn:starts-with('query', 'query')	true
fn:starts-with('query', 'u')	false
fn:starts-with('query', '')	true
fn:starts-with('', 'query')	false
fn:starts-with('', '')	true
fn:starts-with('query', ())	true
fn:starts-with(' query', 'q')	false
fn:starts-with("Query", "que")	false