ForEach

struct · iOS 13.0+ · SDK 27.1

struct ForEach<Data, ID, Content> where Data : RandomAccessCollection, ID : Hashable

A structure that computes views on demand from an underlying collection of identified data. Use `ForEach` to provide views based on a <doc://com.apple.documentation/documentation/Swift/RandomAccessCollection> of some data type. Either the collection's elements must conform to <doc://com.apple.documentation/documentation/Swift/Identifiable> or you need to provide an `id` parameter to the `ForEach` initializer. The following example creates a `NamedFont` type that conforms to <doc://com.apple.documentation/documentation/Swift/Identifiable>, and an array of this type called `namedFonts`. A `ForEach` instance iterates over the array, producing new ``Text`` instances that display examples of each SwiftUI ``Font`` style provided in the array. private struct NamedFont: Identifiable { let name: String let font: Font var id: String { name } } private let namedFonts: [NamedFont] = [ NamedFont(name: "Large Title", font: .largeTitle), NamedFont(name: "Title", font: .title), NamedFont(name: "Headline", font: .headline), NamedFont(name: "Body", font: .body), NamedFont(name: "Caption", font: .caption) ] var body: some View { ForEach(namedFonts) { namedFont in Text(namedFont.name) .font(namedFont.font) } }  Some containers like ``List`` or ``LazyVStack`` will query the elements within a for each lazily. To obtain maximal performance, ensure that the view created from each element in the collection represents a constant number of views. For example, the following view uses an if statement which means each element of the collection can represent either 1 or 0 views, a non-constant number. ForEach(namedFonts) { namedFont in if namedFont.name.count != 2 { Text(namedFont.name) } } You can make the above view represent a constant number of views by wrapping the condition in a ``VStack``, an ``HStack``, or a ``ZStack``. ForEach(namedFonts) { namedFont in VStack { if namedFont.name.count != 2 { Text(namedFont.name) } } } When enabling the following launch argument, SwiftUI will log when it encounters a view that produces a non-constant number of views in these containers: -LogForEachSlowPath YES

Members (0)

This type has no directly callable members in this snapshot. See the framework’s skipped declarations for unsupported APIs.

All SwiftUICore types →