---
title: "subscript(_:)"
framework: swiftui
role: symbol
role_heading: Instance Subscript
path: "swiftui/containervalues/subscript(_:)"
---

# subscript(_:)

Accesses the particular container value associated with a custom key.

## Declaration

```swift
subscript<Key>(key: Key.Type) -> Key.Value where Key : ContainerValueKey { get set }
```

## Overview

Overview Create a custom container value by declaring a new property in an extension to the container values structure and applying the Entry() macro to the variable declaration: extension ContainerValues {     @Entry var myCustomValue: String = "Default value" } You use custom container values the same way you use system-provided values, setting a value with the containerValue(_:_:) view modifier, and reading values from a Subview provided by the subviews modifier. You can also provide a dedicated view modifier as a convenience for setting the value: extension View {     func myCustomValue(_ myCustomValue: String) -> some View {         containerValue(\.myCustomValue, myCustomValue)     } }