scala

问题 I am trying to get tensorflow for java to work on Scala. I am use the tensorflow java library without any wrapper for Scala. At sbt I have: If I run the HelloWord found here, it WORKS fine, with the Scala adaptations: import org.tensorflow.Graph import org.tensorflow.Session import org.tensorflow.Tensor import org.tensorflow.TensorFlow val g = new Graph() val value = "Hello from " + TensorFlow.version() val t = Tensor.create(value.getBytes("UTF-8")) // The Java API doesn't yet include

问题 I have two lists val a = List(1,2,3) val b = List(5,6,7) I'd like to create a Map like: val h = Map(1->5, 2->6, 3->7) basically iterating thru both the lists and assigning key value pairs. How to do it properly in Scala? 回答1: You can zip the lists together into a list of tuples, then call toMap : (a zip b) toMap Note that if one list is longer than the other, it will be truncated. Example: val a = List(1, 2, 3) val b = List(5, 6, 7) scala> (a zip b) toMap res2: scala.collection.immutable.Map

问题 I have two lists val a = List(1,2,3) val b = List(5,6,7) I'd like to create a Map like: val h = Map(1->5, 2->6, 3->7) basically iterating thru both the lists and assigning key value pairs. How to do it properly in Scala? 回答1: You can zip the lists together into a list of tuples, then call toMap : (a zip b) toMap Note that if one list is longer than the other, it will be truncated. Example: val a = List(1, 2, 3) val b = List(5, 6, 7) scala> (a zip b) toMap res2: scala.collection.immutable.Map

问题 I have two lists val a = List(1,2,3) val b = List(5,6,7) I'd like to create a Map like: val h = Map(1->5, 2->6, 3->7) basically iterating thru both the lists and assigning key value pairs. How to do it properly in Scala? 回答1: You can zip the lists together into a list of tuples, then call toMap : (a zip b) toMap Note that if one list is longer than the other, it will be truncated. Example: val a = List(1, 2, 3) val b = List(5, 6, 7) scala> (a zip b) toMap res2: scala.collection.immutable.Map

问题 I have two lists val a = List(1,2,3) val b = List(5,6,7) I'd like to create a Map like: val h = Map(1->5, 2->6, 3->7) basically iterating thru both the lists and assigning key value pairs. How to do it properly in Scala? 回答1: You can zip the lists together into a list of tuples, then call toMap : (a zip b) toMap Note that if one list is longer than the other, it will be truncated. Example: val a = List(1, 2, 3) val b = List(5, 6, 7) scala> (a zip b) toMap res2: scala.collection.immutable.Map

问题 I have two lists val a = List(1,2,3) val b = List(5,6,7) I'd like to create a Map like: val h = Map(1->5, 2->6, 3->7) basically iterating thru both the lists and assigning key value pairs. How to do it properly in Scala? 回答1: You can zip the lists together into a list of tuples, then call toMap : (a zip b) toMap Note that if one list is longer than the other, it will be truncated. Example: val a = List(1, 2, 3) val b = List(5, 6, 7) scala> (a zip b) toMap res2: scala.collection.immutable.Map

问题 On Type Level, i stumble upon the following: sealed abstract class StSource[A] { type S def init: S // create the initial state def emit(s: S): (A, S) // emit a value, and update state } object StSource { type Aux[A, S0] = StSource[A] {type S = S0} def apply[A, S0](i: S0)(f: S0 => (A, S0)): Aux[A, S0] = new StSource[A] { type S = S0 def init = i def emit(s: S0) = f(s) } } The line that intrigued me is type Aux[A, S0] = StSource[A] {type S = S0} In paerticular {type S = S0} in StSource[A]

问题 On Type Level, i stumble upon the following: sealed abstract class StSource[A] { type S def init: S // create the initial state def emit(s: S): (A, S) // emit a value, and update state } object StSource { type Aux[A, S0] = StSource[A] {type S = S0} def apply[A, S0](i: S0)(f: S0 => (A, S0)): Aux[A, S0] = new StSource[A] { type S = S0 def init = i def emit(s: S0) = f(s) } } The line that intrigued me is type Aux[A, S0] = StSource[A] {type S = S0} In paerticular {type S = S0} in StSource[A]

问题 On Type Level, i stumble upon the following: sealed abstract class StSource[A] { type S def init: S // create the initial state def emit(s: S): (A, S) // emit a value, and update state } object StSource { type Aux[A, S0] = StSource[A] {type S = S0} def apply[A, S0](i: S0)(f: S0 => (A, S0)): Aux[A, S0] = new StSource[A] { type S = S0 def init = i def emit(s: S0) = f(s) } } The line that intrigued me is type Aux[A, S0] = StSource[A] {type S = S0} In paerticular {type S = S0} in StSource[A]

问题 I am trying to enforce a rule that the (dependent) return type of a typeclass, must itself implement a typeclass. So when the user implements the IsVec typeclass below, they must also ensure that the return value of the getElem method implements another typeclass ( IsVecElem ). My attempts to make this work look something like this: // A typeclass for an vector element abstract class IsVecElem[A, T: Numeric] { def dataOnly(self: A): T } // A typeclass for a vector abstract class IsVec[A, T: