XPath function
substring-before()
Everything before the first occurrence of a marker — and the empty string when the marker is absent, which is not an error you will notice.
substring-before(s, m) returns the part of s that precedes the first m. It is the standard way to split a delimited value without regular expressions.
When m does not occur, the result is the empty string. That failure is silent, so a mistyped delimiter produces empty output rather than a complaint.
- Syntax
substring-before(string, marker) → string- Returns
- string
- Kind
- Function
- Version
- XPath 1.0 (libxml2)
Worked examples
Each result below is what the evaluator returned, asserted on every test run. An empty result means an empty node-set — which is an answer, not an error.
The sample documents
Every example on this page runs against this document. The sitemap one is namespaced on purpose — almost every real XML document is, and that changes which expressions match.
<?xml version="1.0" encoding="UTF-8"?>
<order id="A-1001" tier="gold">
<customer country="NO">Ada Lovelace</customer>
<lines>
<line sku="WIDGET-1" qty="2"><price>14.50</price></line>
<line sku="WIDGET-2" qty="1"><price>39.00</price></line>
<line sku="GIFT-WRAP" qty="1"><price>0.00</price></line>
</lines>
<note> Deliver after 09:00 </note>
</order>Related
- substring-after()Everything after the first occurrence of a marker. Empty when the marker is absent.
- substring()A slice of a string, indexed from 1 — not from 0, which is the mistake that shifts every result by one character.
- contains()Whether one string occurs inside another. The most-used XPath function, and the one most often given its arguments the wrong way round.
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