--- title: The longer I work with Swift, the more I appreciate... description: Swift's Copy-on-Write (CoW) mechanism allows value types like Array to avoid actual memory copies until a mutation occurs. This lazy copying strategy is key to... canonical: https://daily.dev/posts/the-longer-i-work-with-swift-the-more-i-appreciate-copy-on-write-akjympzke twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: The longer I work with Swift, the more I appreciate Copy-on-Write | daily.dev og:description: Swift's Copy-on-Write (CoW) mechanism allows value types like Array to avoid actual memory copies until a mutation occurs. This lazy copying strategy is key to... og:url: https://daily.dev/posts/the-longer-i-work-with-swift-the-more-i-appreciate-copy-on-write-akjympzke og:image: https://api.daily.dev/og/posts/akjympzKe.png og:image:alt: The longer I work with Swift, the more I appreciate Copy-on-Write og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # The longer I work with Swift, the more I appreciate Copy-on-Write **[iOS Developers](https://daily.dev/sources/ios_dev)** · [@divyesh_vekariya](https://daily.dev/divyesh_vekariya) · 1 min read · 13 upvotes · 0 comments ## Summary Swift's Copy-on-Write (CoW) mechanism allows value types like Array to avoid actual memory copies until a mutation occurs. This lazy copying strategy is key to why Swift value types are both safe and performant, making CoW an essential concept for Swift developers to understand. ## Content What if I told you that copying an Array in Swift often doesn't create a copy at all? That's the magic of Copy-on-Write. Swift delays copying data until a mutation actually occurs, giving you both safety and performance. If you want to understand why Swift value types are so efficient, CoW is a concept you can't skip. [https://medium.com/@dkvekariya/understanding-copy-on-write-cow-in-swift-0db09995edef](https://medium.com/@dkvekariya/understanding-copy-on-write-cow-in-swift-0db09995edef) #Swift #iOS #Performance #Programming --- Tags: [#performance](https://daily.dev/tags/performance), [#ios](https://daily.dev/tags/ios), [#swift](https://daily.dev/tags/swift) [View this post on daily.dev](https://daily.dev/posts/the-longer-i-work-with-swift-the-more-i-appreciate-copy-on-write-akjympzke) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/the-longer-i-work-with-swift-the-more-i-appreciate-copy-on-write-akjympzke","headline":"The longer I work with Swift, the more I appreciate Copy-on-Write","text":"Swift's Copy-on-Write (CoW) mechanism allows value types like Array to avoid actual memory copies until a mutation occurs. 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