Examples for zipN, zipWithN and zipAll (#28510)

akka-docs/src/test/java/jdocs/stream/operators/source/Zip.java

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+/*
+ * Copyright (C) 2009-2020 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package jdocs.stream.operators.source;
+
+import akka.NotUsed;
+import akka.actor.ActorSystem;
+import akka.stream.javadsl.Source;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class Zip {
+
+  void zipNSample() {
+    ActorSystem system = null;
+
+    // #zipN-simple
+    Source<Object, NotUsed> chars = Source.from(Arrays.asList("a", "b", "c", "e", "f"));
+    Source<Object, NotUsed> numbers = Source.from(Arrays.asList(1, 2, 3, 4, 5, 6));
+    Source<Object, NotUsed> colors =
+        Source.from(Arrays.asList("red", "green", "blue", "yellow", "purple"));
+
+    Source.zipN(Arrays.asList(chars, numbers, colors)).runForeach(System.out::println, system);
+    // prints:
+    // [a, 1, red]
+    // [b, 2, green]
+    // [c, 3, blue]
+    // [e, 4, yellow]
+    // [f, 5, purple]
+
+    // #zipN-simple
+  }
+
+  void zipWithNSample() {
+    ActorSystem system = null;
+
+    // #zipWithN-simple
+    Source<Integer, NotUsed> numbers = Source.from(Arrays.asList(1, 2, 3, 4, 5, 6));
+    Source<Integer, NotUsed> otherNumbers = Source.from(Arrays.asList(5, 2, 1, 4, 10, 4));
+    Source<Integer, NotUsed> andSomeOtherNumbers = Source.from(Arrays.asList(3, 7, 2, 1, 1));
+
+    Source.zipWithN(
+            (List<Integer> seq) -> seq.stream().mapToInt(i -> i).max().getAsInt(),
+            Arrays.asList(numbers, otherNumbers, andSomeOtherNumbers))
+        .runForeach(System.out::println, system);
+    // prints:
+    // 5
+    // 7
+    // 3
+    // 4
+    // 10
+
+    // #zipWithN-simple
+  }
+
+  void zipAllSample() {
+    ActorSystem system = null;
+    // #zipAll-simple
+
+    Source<Integer, NotUsed> numbers = Source.from(Arrays.asList(1, 2, 3, 4));
+    Source<String, NotUsed> letters = Source.from(Arrays.asList("a", "b", "c"));
+
+    numbers.zipAll(letters, -1, "default").runForeach(System.out::println, system);
+    // prints:
+    // Pair(1,a)
+    // Pair(2,b)
+    // Pair(3,c)
+    // Pair(4,default)
+    // #zipAll-simple
+  }
+}

akka-docs/src/test/scala/docs/stream/operators/source/Zip.scala

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+/*
+ * Copyright (C) 2009-2020 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package docs.stream.operators.source
+
+import akka.NotUsed
+import akka.actor.typed.ActorSystem
+import akka.stream.scaladsl.Source
+
+object Zip {
+
+  implicit val system: ActorSystem[_] = ???
+
+  def zipN(): Unit = {
+    // #zipN-simple
+    val chars = Source("a" :: "b" :: "c" :: "e" :: "f" :: Nil)
+    val numbers = Source(1 :: 2 :: 3 :: 4 :: 5 :: 6 :: Nil)
+    val colors = Source("red" :: "green" :: "blue" :: "yellow" :: "purple" :: Nil)
+
+    Source.zipN(chars :: numbers :: colors :: Nil).runForeach(println)
+    // prints:
+    // Vector(a, 1, red)
+    // Vector(b, 2, green)
+    // Vector(c, 3, blue)
+    // Vector(e, 4, yellow)
+    // Vector(f, 5, purple)
+
+    // #zipN-simple
+  }
+
+  def zipNWith(): Unit = {
+    // #zipWithN-simple
+    val numbers = Source(1 :: 2 :: 3 :: 4 :: 5 :: 6 :: Nil)
+    val otherNumbers = Source(5 :: 2 :: 1 :: 4 :: 10 :: 4 :: Nil)
+    val andSomeOtherNumbers = Source(3 :: 7 :: 2 :: 1 :: 1 :: Nil)
+
+    Source
+      .zipWithN((seq: Seq[Int]) => seq.max)(numbers :: otherNumbers :: andSomeOtherNumbers :: Nil)
+      .runForeach(println)
+    // prints:
+    // 5
+    // 7
+    // 3
+    // 4
+    // 10
+
+    // #zipWithN-simple
+  }
+
+  def zipAll() {
+    // #zipAll-simple
+    val numbers = Source(1 :: 2 :: 3 :: 4 :: Nil)
+    val letters = Source("a" :: "b" :: "c" :: Nil)
+
+    numbers.zipAll(letters, -1, "default").runForeach(println)
+    // prints:
+    // (1,a)
+    // (2,b)
+    // (3,c)
+    // (4,default)
+    // #zipAll-simple
+  }
+}