# select(_:_:) Adds a tensor-tensor select operation to the current graph. ``` func select(_ valueIfTrue: BNNSGraph.Builder.Tensor, _ valueIfFalse: BNNSGraph.Builder.Tensor) -> BNNSGraph.Builder.Tensor 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 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)) ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)