Go/Arrays

Go blog post: arrays, slices, and strings: https://blog.golang.org/slices

Basics

Initialization

The most important thing to understand about arrays is that they are different from slices.

If we create the variable like this:

var keys [3]int

it is an array type. That's because we've specified the precise capacity that keys should have.

But if we create the variable like this:

var keys []int

it is a slice type. That's because we did not specify the capacity.

In both cases, we have not actually initialized the value of either variable. Here's how we create an array:

keys := [3]int{10,20,30}

Array size is a part of the type

An important characteristic of arrays is that their size is a part of their type.

"Arrays are not often seen in Go programs because the size of an array is part of its type, which limits its expressive power."

The two variables defined here are of two distinct types:

var buffer [256]byte
var buffer2 [512]byte

This is because the size of the array is allocated at initialization time. You can use the square bracket syntax to access elements of an array, buffer[0] through buffer[255]. The program crashes if you access an index outside of its range.

Array slices

See Go/Slices

Comparison

Let's cover how to compare arrays.

Array values are comparable if values of the array element type are comparable.

Two array values are equal if their corresponding elements are equal.

However, note that you cannot compare slices: https://play.golang.org/p/Kk8osjPm8n

Likewise: https://play.golang.org/p/kCVoPekPudc