Description
The fn:zero-or-one function returns $arg if it contains zero or one items. Otherwise, the error FORG0003 is raised. This function is useful when static typing is in effect, to avoid apparent static type errors.
This description is © Copyright 2007, O'Reilly Media. 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| Name | Type |
|---|
$arg |
item()* |
| return value |
item()? |
Examples| XSLT Example | Results |
|---|
zero-or-one( () )
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()
|
zero-or-one('a')
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a
|
zero-or-one( ('a', 'b') )
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Error FORG0003 |
See Also| fn:one-or-more | Returns a sequence if it contains one or more items, otherwise errors | | fn:exactly-one | Returns a sequence if it contains exactly one item, otherwise errors |
History |
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