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fn:boolean

The effective boolean value of a sequence

Description

The fn:boolean function calculates the effective boolean value of a sequence. In most cases it is unnecessary to call this function because the effective boolean value is calculated automatically in many expressions, including conditional and logical expressions, where clauses, and predicates.

This description is © Copyright 2007, Priscilla Walmsley. It is excerpted from the book XQuery by Priscilla Walmsley, O'Reilly, 2007. For a complete explanation of this function, please refer to Appendix A of the book.

Arguments and Return Type

Examples

doc('https://www.datypic.com/functx./input/order.xml')

boolean( () )

false

boolean('')

false

boolean(0)

false

boolean('0')

true

boolean('false')

true

boolean(xs:float('NaN'))

false

boolean((false(), false(), false()))

boolean($ordDoc/order[1])

true

boolean($ordDoc/noSuchChild)

false

boolean(<a>false</a>)

true

See Also

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