---
title: "select(_:_:)"
framework: accelerate
role: symbol
role_heading: Instance Method
path: "accelerate/bnnsgraph/builder/tensor/select(_:_:)-1fiqe"
---

# select(_:_:)

Adds a tensor-tensor select operation to the current graph.

## Declaration

```swift
func select<U>(_ valueIfTrue: BNNSGraph.Builder.Tensor<U>, _ valueIfFalse: BNNSGraph.Builder.Tensor<U>) -> BNNSGraph.Builder.Tensor<U> where U : BNNSScalar
```

## Parameters

- `valueIfTrue`: The values that the operation returns when the corresponding value in self is true.
- `valueIfFalse`: The values that the operation returns when the corresponding value in self is false.

## Discussion

Discussion For example, the following code returns the valueIfTrue elements when the corresponding elements in z are true and the elements in valueIfFalse when the corresponding elements in z are false: let ctx = try BNNSGraph.makeContext {

builder in

let z = builder.argument(dataType: Bool.self, shape: [8])

let x = builder.argument(dataType: Float.self, shape: [8])     let y = builder.argument(dataType: Float.self, shape: [8])

let masked = z.select(x, y)

return [ masked ] }

let z = BNNSTensor.allocate(initializingFrom: [true, true, false, false,                                                true, true, false, false],                             shape: [8], stride: [1])

let x = BNNSTensor.allocate(initializingFrom: [1, 2, 3, 4, 5, 6, 7, 8] as [Float],                             shape: [8], stride: [1]) let y = BNNSTensor.allocate(initializingFrom: [10, 20, 30, 40, 50, 60, 70, 80] as [Float],                             shape: [8], stride: [1])

let tensor_tensor = BNNSTensor.allocateUninitialized(scalarType: Float.self, shape: [8], stride: [1])

var args = [tensor_tensor, tensor_scalar, scalar_tensor, z, x, y]

try ctx.executeFunction(arguments: &args)

// Prints "[1.0, 2.0, 30.0, 40.0, 5.0, 6.0, 70.0, 80.0]". print(tensor_tensor.makeArray(of: Float.self))