Anonymous Functions in Golang

Introduction

An Anonymous function is a function that does not have a name. These functions are used when you want to write your logic inline. An anonymous function is not accessible after its initial creation, it can only be accessed by a variable it is stored in as a function as a value. An anonymous function can also have multiple arguments and return values.

Golang Anonymous Function

Golang allows you to create in-line or anonymous functions for short-term use. This function can have input parameters and return values just like any other function.

We can create an Anonymous function using the below syntax.

Syntax

Examples

Normal Anonymous Function

The below code shows a basic anonymous function declaration that prints a string to the console.

Output:

Normal anonymous function example : playground link

Assigning the Anonymous Function to a Variable

Golang anonymous functions can be assigned to a variable and then it can be invoked using the same variable. The below examples show how we can assign a function to a variable and invoke it.

Output:

Assigning the anonymous function to a variable example: playground link

Pass Arguments in the Anonymous Function

Golang supports passing arguments to anonymous functions. The below code shows how we can pass a string to an anonymous function and print the concatenated string to the console.

Output:

Pass arguments in the anonymous function example: playground link

Return Value from Anonymous Function

Just like we can have input arguments for anonymous functions we can also return values from those. The below example illustrates how we can return values from anonymous functions.

Output:

Return Value From Anonymous Function example: playground link

Pass an Anonymous Function as an Argument into Other Function

Golang supports passing anonymous functions as other functions' arguments. we need to add the argument details in the function signature as shown in the example.

Output:

Pass an anonymous function as an argument into another function example: playground link

Return an Anonymous Function from Another Function

We can return an anonymous function from another function. This can be achieved by returning a function shown in the below example.

Output:

Return an anonymous function from another function example : playground link