subsequence
A portion of a sequence based on a starting point and length
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)].
Parameters |
Description |
|---|---|
sourceSeq:item() |
the entire sequence |
startingLoc:double() |
the starting item position (1-based) |
length:double() |
the number of items to include |
Examples
XPath |
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) |
() |