---
title: USDLayer.PathExpression
framework: usdkit
role: symbol
role_heading: Structure
path: usdkit/usdlayer/pathexpression
---

# USDLayer.PathExpression

A boolean expression over path patterns for selecting sets of prims.

## Declaration

```swift
struct PathExpression
```

## Overview

Overview Path expressions combine patterns using set operations (union, intersection, complement, difference) and can reference other named expressions. The struct wraps pxr::SdfPathExpression and provides access to common expression patterns through static properties and string-based initialization.

## Topics

### Initializers

- [init()](usdkit/usdlayer/pathexpression/init().md)
- [init(_:)](usdkit/usdlayer/pathexpression/init(_:).md)

### Instance Properties

- [isEmpty](usdkit/usdlayer/pathexpression/isempty.md)
- [text](usdkit/usdlayer/pathexpression/text.md)

### Type Properties

- [everyDescendant](usdkit/usdlayer/pathexpression/everydescendant.md)
- [everything](usdkit/usdlayer/pathexpression/everything.md)
- [nothing](usdkit/usdlayer/pathexpression/nothing.md)
- [weakerReference](usdkit/usdlayer/pathexpression/weakerreference.md)

## Relationships

### Conforms To

- [Copyable](swift/copyable.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Escapable](swift/escapable.md)
- [ExpressibleByExtendedGraphemeClusterLiteral](swift/expressiblebyextendedgraphemeclusterliteral.md)
- [ExpressibleByStringLiteral](swift/expressiblebystringliteral.md)
- [ExpressibleByUnicodeScalarLiteral](swift/expressiblebyunicodescalarliteral.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)
- [USDPrim.Attribute.Value](usdkit/usdprim/attribute/value.md)
- [USDValueProtocol](usdkit/usdvalueprotocol.md)

## See Also

### Accessing scene description by path

- [prim(at:)](usdkit/usdlayer/prim(at:).md)
- [property(at:)](usdkit/usdlayer/property(at:).md)
- [attribute(at:)](usdkit/usdlayer/attribute(at:).md)
- [relationship(at:)](usdkit/usdlayer/relationship(at:).md)
- [spec(at:)](usdkit/usdlayer/spec(at:).md)
- [specType(at:)](usdkit/usdlayer/spectype(at:).md)
- [traverse(at:_:)](usdkit/usdlayer/traverse(at:_:).md)
- [USDLayer.Path](usdkit/usdlayer/path.md)
- [USDLayer.Spec](usdkit/usdlayer/spec.md)
- [USDLayer.SpecType](usdkit/usdlayer/spectype.md)