zipWith

Combines elements from multiple sources through a combine function and passes the returned value downstream.

Fan-in operators

Signature

Source.zipWith Flow.zipWith

Description

Combines elements from multiple sources through a combine function and passes the returned value downstream.

See also:

Examples

Scala
Java
sourceimport org.apache.pekko
import pekko.stream.scaladsl.Source
import pekko.stream.scaladsl.Sink

    val sourceCount = Source(List("one", "two", "three"))
    val sourceFruits = Source(List("apple", "orange", "banana"))

    sourceCount
      .zipWith(sourceFruits) { (countStr, fruitName) =>
        s"$countStr $fruitName"
      }
      .runWith(Sink.foreach(println))
    // this will print 'one apple', 'two orange', 'three banana'
sourceimport org.apache.pekko.stream.javadsl.Keep;
import org.apache.pekko.stream.javadsl.Source;
import org.apache.pekko.stream.javadsl.Sink;

import java.util.*;

Source<String, NotUsed> sourceCount = Source.from(Arrays.asList("one", "two", "three"));
Source<String, NotUsed> sourceFruits = Source.from(Arrays.asList("apple", "orange", "banana"));
sourceCount
    .zipWith(
        sourceFruits,
        (Function2<String, String, String>) (countStr, fruitName) -> countStr + " " + fruitName)
    .runForeach(System.out::println, system);
// this will print 'one apple', 'two orange', 'three banana'

Reactive Streams semantics

emits when all of the inputs have an element available

backpressures both upstreams when downstream backpressures but also on an upstream that has emitted an element until the other upstream has emitted an element

completes when any upstream completes

1.1.3