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contains

The contains function in XQuery is used to determine whether one string contains another substring. This function determines if the main string contains at least one occurrence of the specified substring. It evaluates to a boolean value indicating the presence or absence of a substring within a larger string.

Syntax

fn:contains(arg1, arg2, collation)

The following table describes the argument for this command:

Argument	Required/Optional	Description
arg1	Required	The main string to check for the presence of another substring. If it is empty-sequence() , it is treated as an empty string.
arg2	Required	The substring to find within $arg1 . This is the substring you are searching for. If it is empty-sequence() , it is treated as an empty string.
collation	Optional	A URI that specifies the collation to be used when comparing strings. Collations define locale-specific rules for string comparison. If omitted, the default collation is used.

Return Value

Returns a boolean value indicating whether at least one sequence of collation units in

$arg1

minimally matches the collation units in

$arg2

, including matches at the beginning or end, as determined by the specified or default collation.

Returns

true

$arg2

is found within

$arg1

Returns

false

$arg2

is not found within

$arg1

Returns

false

if either

$arg1

$arg2

is the empty sequence

()

$collation

is provided, the substring search uses the specified collation rules.

If invalid collation URI is provided, an error is raised.

Examples

The following table lists some sample values and return values:

SAMPLE FUNCTION	OUTPUT
fn:contains('query', 'e')	true
fn:contains('query', 'ery')	true
fn:contains('query', 'query')	true
fn:contains("Hello", "hel")	false
fn:contains('query', 'x')	false
fn:contains('query', '')	true
fn:contains('query', ())	true
fn:contains( (), 'q')	false