---
title: "map(_:_:)"
framework: combine
role: symbol
role_heading: Instance Method
path: "combine/publisher/map(_:_:)"
---

# map(_:_:)

Publishes the values of two key paths as a tuple.

## Declaration

```swift
func map<T0, T1>(_ keyPath0: KeyPath<Self.Output, T0>, _ keyPath1: KeyPath<Self.Output, T1>) -> Publishers.MapKeyPath2<Self, T0, T1>
```

## Parameters

- `keyPath0`: The key path of a property on Output.
- `keyPath1`: The key path of another property on Output.

## Return Value

Return Value A publisher that publishes the values of two key paths as a tuple.

## Discussion

Discussion In the following example, the map(_:_:) operator uses the Swift key path syntax to access the die1 and die2 members of the DiceRoll structure published by the Just publisher. The downstream sink subscriber receives only these two values (as an (Int, Int) tuple), not the entire DiceRoll. struct DiceRoll {     let die1: Int     let die2: Int }

cancellable = Just(DiceRoll(die1:Int.random(in:1...6),                             die2: Int.random(in:1...6)))     .map(\.die1, \.die2)     .sink { values in         print ("Rolled: \(values.0), \(values.1) (total: \(values.0 + values.1))")     } // Prints "Rolled: 6, 4 (total: 10)" (or other random values).

## See Also

### Identifying properties with key paths

- [map(_:)](combine/publisher/map(_:)-6sm0a.md)
- [map(_:_:_:)](combine/publisher/map(_:_:_:).md)