go-stream

Overview

Go-Stream is a stream processing library to implement the Java Stream API with Go.

Features

• non-storage: Stream is not a data structure, but the view of the data source. The data source can come from slice, map or supplier function.
• pipeline: Operate the elements through pipeline, support short-circuit and parallel execution.
• lazy-evaluation: The intermediate operation on the stream is lazy, and it will be truly executed only when the terminal operation is performed.

Go-Stream supports the following operations

Stream Operation
Intermediate operations	Stateless	Filter、Map、Peek、FlatMap
	Stateful	Distinct、Sorted、Skip、Limit、TakeWhile、DropWhile
Terminal operations	non short-circuiting	ForEach、Reduce、ReduceFromIdentity、Count、Max、Min、FindLast、ToSlice、ToMap、GroupingBy
	short-circuiting	AllMatch、AnyMatch、NoneMatch、FindFirst

Quick Start

1. installation go-stream library

go get github.com/chinalhr/go-stream

2. import

import "github.com/chinalhr/go-stream"

3. Use Stream to process data

	type widget struct {
		color  string
		weight int
	}

	widgets := []widget{
		{
			color:  "yellow",
			weight: 4,
		},
		{
			color:  "red",
			weight: 3,
		},
		{
			color:  "yellow",
			weight: 2,
		},
		{
			color:  "blue",
			weight: 1,
		},
	}

	sum := stream.OfSlice(widgets).
		Filter(func(e types.T) bool {
			return e.(widget).color == "yellow"
		}).
		Map(func(e types.T) (r types.R) {
			return e.(widget).weight
		}).
		Reduce(func(e1 types.T, e2 types.T) types.T {
			return e1.(int) + e2.(int)
		})