---
title: "difference(from:by:)"
framework: swift-package-manager
role: symbol
role_heading: Instance Method
path: "swift-package-manager/documentation/packageplugin/filelist/difference(from:by:)"
---

# difference(from:by:)

Inherited from BidirectionalCollection.difference(from:by:).

## Declaration

```swift
func difference<C>(from other: C, by areEquivalent: (C.Element, Self.Element) -> Bool) -> CollectionDifference<Self.Element> where C : BidirectionalCollection, Self.Element == C.Element
```