The Complete Go Learning Guide

Go (also called Golang) is a compiled, statically typed programming language designed for clear software and efficient tools. It is popular for network services, cloud systems, and command-line programs.

How Go works

The Go compiler turns source files into an executable. Go uses packages to group code, has a built-in garbage collector, and includes language features for concurrent tasks.

What you will learn

You will progress from a first executable through functions, structs, slices, maps, packages, errors, concurrency, and practical projects.

How to use this guide

1. Start with Chapter 1 and move through the chapters in order. New ideas build on the earlier ones.
2. Type each example yourself, make a small change, and predict what will happen before running it.
3. When a chapter is ready, its lesson will appear at the chapter link. These pages are currently blank lesson starters.

A step-by-step learning path

1. Chapters 1-7: Learn to write Go programs. Run a program, use values and types, work with input and output, control repetition, and write functions.
2. Chapters 8-12: Work with collections and data. Use arrays, slices and maps, process text, understand pointers, manage resources, and define structs and interfaces.
3. Chapters 13-18: Organize practical tools. Learn visibility, packages and modules, the standard library, files, error handling, debugging, and tests.
4. Chapters 19-24: Build reliable programs. Study algorithms, advanced Go features, concurrency and performance, build workflows, and guided projects.

Go ideas you will meet early

• Package: a group of related Go source files. A runnable program uses the main package and starts in its main function.
• Short declaration: := creates and initializes a local variable, for example name := "Ada".
• Slice: a flexible view of a sequence of values. A map stores values under keys.
• Error value: many Go functions return an error as a result. Programs usually check that result and decide what to do if it is not nil.

Your first Go program

Save this program as hello.go:

package main

import "fmt"

func main() {
    fmt.Println("Hello, world!")
}

package main marks this as a runnable program. The fmt package provides formatted input and output. Execution starts in main, and fmt.Println writes text followed by a new line. With Go installed, run it from the file's folder:

go run hello.go

Go's formatter can keep source code consistent. As your program grows beyond one file, use a Go module to describe the project and its dependencies.

A simple way to study

• Check every returned error instead of assuming an operation succeeded.
• Format code with gofmt and learn the package name at the top of each source file.
• Try go test when you begin adding tests to a package.
• Learn concurrency gradually; goroutines and channels are useful tools, but they do not remove the need to reason about shared data.

First file: save your first program as hello.go and run it with go run hello.go.