Description
The fn:subsequence function returns a sequence of $length items of $sourceSeq , starting at the position $startingLoc . The first item in the sequence is considered to be at position 1, not 0. If no $length is passed, or if $length is greater than the number of items that can be returned, the function includes items to the end of the sequence. An alternative to calling the fn:subsequence function is using a predicate. For example, fn:subsequence($a,3,4) is equivalent to $a[position() = (3 to 7)] .
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 TypeName | Type | Description |
$sourceSeq |
item()* |
the entire sequence |
$startingLoc |
xs:double |
the starting item position (1-based) |
$length |
xs:double |
the number of items to include |
return value |
item()* |
ExamplesXQuery Example | Results |
---|
subsequence(
('a', 'b', 'c', 'd', 'e'), 3) |
('c', 'd', 'e') |
subsequence(
('a', 'b', 'c', 'd', 'e'), 3, 2) |
('c', 'd') |
subsequence(
('a', 'b', 'c', 'd', 'e'), 3, 10) |
('c', 'd', 'e') |
subsequence(
('a', 'b', 'c', 'd', 'e'), 10) |
() |
subsequence(
('a', 'b', 'c', 'd', 'e'), -2, 5) |
('a', 'b') |
subsequence( (), 3) |
() |
History |
Recommended Reading:
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