lostluck commented on a change in pull request #11866: URL: https://github.com/apache/beam/pull/11866#discussion_r432739513
########## File path: learning/katas/go/Core Transforms/Combine/Simple Function/task.md ########## @@ -0,0 +1,43 @@ +<!-- + ~ Licensed to the Apache Software Foundation (ASF) under one + ~ or more contributor license agreements. See the NOTICE file + ~ distributed with this work for additional information + ~ regarding copyright ownership. The ASF licenses this file + ~ to you under the Apache License, Version 2.0 (the + ~ "License"); you may not use this file except in compliance + ~ with the License. You may obtain a copy of the License at + ~ + ~ http://www.apache.org/licenses/LICENSE-2.0 + ~ + ~ Unless required by applicable law or agreed to in writing, software + ~ distributed under the License is distributed on an "AS IS" BASIS, + ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + ~ See the License for the specific language governing permissions and + ~ limitations under the License. + --> + +# Combine - Simple Function + +Combine is a Beam transform for combining collections of elements or values in your data. When you +apply a Combine transform, you must provide the function that contains the logic for combining the +elements or values. The combining function should be commutative and associative, as the function +is not necessarily invoked exactly once on all values with a given key. Because the input data +(including the value collection) may be distributed across multiple workers, the combining function +might be called multiple times to perform partial combining on subsets of the value collection. + +Simple combine operations, such as sums, can usually be implemented as a simple function. + +**Kata:** Implement the summation of numbers using +[beam.Combine](https://godoc.org/github.com/apache/beam/sdks/go/pkg/beam#Combine). + +<div class="hint"> + Implement a combine function compatible with the + <a href="https://godoc.org/github.com/apache/beam/sdks/go/pkg/beam#Combine";> + beam.Combine</a> method that performs the summation of an Iterable. Review comment: Technically, the iterables are hidden in the Go SDK. The SDK only supports merge functions at this time. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
