Go Programming Language For Dummies

Chapter 8

Establishing Relationships Using Maps

IN THIS CHAPTER

Seeing how to create maps in Go

Creating and sorting a map of structs

In earlier chapters, I fill you in on arrays and slices, where the position of items is important, and items are accessed by their locations. A map, on the other hand, is a hash table that stores data in an associative manner. Items in a map are not accessed according to their positions. Instead, you use keys (a set of unique value that identifies the elements in a map). Maps make adding and removing items extremely easy.

In this chapter, I show you how to work with maps in Go, create a map of structs, and sort a map based on its content.

Creating Maps in Go

A Go map type has the following syntax:

map[keyType] valueType

Here is an example of a map variable that stores a collection of int values with the key that is of the type string:

package main var heights map[string]int func main() { }

Because the map type is a reference type, you need to first initialize it using the make() function before you can use it:

heights = make(map[string]int)

By default, the map variable (heights) is pointing to nil before you initialize it using the make() function. ...