---
title: "~=(_:_:)"
framework: swift
role: symbol
role_heading: Operator
path: "swift/~=(_:_:)"
---

# ~=(_:_:)

Returns a Boolean value indicating whether two arguments match by value equality.

## Declaration

```swift
func ~= <T>(a: T, b: T) -> Bool where T : Equatable
```

## Discussion

Discussion The pattern-matching operator (~=) is used internally in case statements for pattern matching. When you match against an Equatable value in a case statement, this operator is called behind the scenes. let weekday = 3 let lunch: String switch weekday { case 3:     lunch = "Taco Tuesday!" default:     lunch = "Pizza again." } // lunch == "Taco Tuesday!" In this example, the case 3 expression uses this pattern-matching operator to test whether weekday is equal to the value 3. note: In most cases, you should use the equal-to operator (==) to test whether two instances are equal. The pattern-matching operator is primarily intended to enable case statement pattern matching.