Getting Started

Query a Document with XPath

In this tutorial you compile XPath expressions to select elements, use predicates to narrow results, and query namespace-prefixed XML.

XPath selects element nodes exclusively, which means you do not need to filter out whitespace text nodes from the results.

10 mins Estimated Time

Section 1

Select Elements with XPath

xpath(_:namespaces:defaultPrefix:) compiles an XPath expression and returns an XMLPath collection. Because XMLPath conforms to RandomAccessCollection, you can use the full range of Swift collection operations on the result.

Step 1

Parse the XML source and compile a simple XPath expression to select all title elements.

XPathQuery.swift

1import Foundation
2
3func queryTitles() {
4    let xml = """
5    <?xml version="1.0" encoding="UTF-8"?>
6    <catalogue>
7      <book id="1">
8        <title>Clean Code</title>
9        <author>Robert C. Martin</author>
10      </book>
11      <book id="2">
12        <title>The Swift Programming Language</title>
13        <author>Apple Inc.</author>
14      </book>
15    </catalogue>
16    """
17
18    guard let document = XMLDocument(data: Data(xml.utf8)) else { return }
19
20    // Select all title elements anywhere in the document.
21    // XPath returns element nodes only — no text-node filtering needed.
22    if let titles = document.xpath("//title") {
23        for title in titles {
24            print(title.content)
25        }
26    }
27    // Clean Code
28    // The Swift Programming Language
29}

Step 2

Add an attribute predicate to select only the book with id="1".

XPathQuery.swift

1import Foundation
2
3func queryTitles() {
4    let xml = """
5    <?xml version="1.0" encoding="UTF-8"?>
6    <catalogue>
7      <book id="1">
8        <title>Clean Code</title>
9        <author>Robert C. Martin</author>
10      </book>
11      <book id="2">
12        <title>The Swift Programming Language</title>
13        <author>Apple Inc.</author>
14      </book>
15    </catalogue>
16    """
17
18    guard let document = XMLDocument(data: Data(xml.utf8)) else { return }
19
20    // An attribute predicate narrows the selection to a specific book.
21    if let books = document.xpath("//book[@id='1']") {
22        for book in books {
23            let title = book.children.first(where: { $0.name == "title" })?.content ?? ""
24            print(title)
25        }
26    }
27    // Clean Code
28}

Section 2

Query Namespaced Elements

XPath requires an explicit prefix for every namespace in an expression, even when the document uses a default namespace.

Step 1

Parse an Atom feed and use a namespace-aware XPath expression to select atom:title elements.

XPathQuery.swift

1import Foundation
2
3func queryAtomTitles() {
4    let xml = """
5    <?xml version="1.0" encoding="UTF-8"?>
6    <feed xmlns:atom="http://www.w3.org/2005/Atom">
7      <atom:entry>
8        <atom:title>SwiftLibXML 2.0 Released</atom:title>
9        <atom:updated>2026-01-15T00:00:00Z</atom:updated>
10      </atom:entry>
11    </feed>
12    """
13
14    guard let document = XMLDocument(data: Data(xml.utf8)) else { return }
15
16    // Register the namespace prefix explicitly.
17    let ns: [(prefix: String, href: String)] = [
18        ("atom", "http://www.w3.org/2005/Atom")
19    ]
20    if let titles = document.xpath("//atom:title", namespaces: ns) {
21        for title in titles {
22            print(title.content)
23        }
24    }
25    // SwiftLibXML 2.0 Released
26}