DEV Community 👩‍💻👨‍💻

DEV Community 👩‍💻👨‍💻 is a community of 963,673 amazing developers

We're a place where coders share, stay up-to-date and grow their careers.

Create account Log in
Vignesh Muthukumaran
Vignesh Muthukumaran

Posted on

Go Data Types, Structs, Slices

In the last article, we saw some of the very basic constructs of Go. Here, I am gonna go over basic data types and a few aggregated data structures available in Go.

Basic Types in Go

Below are some of the basic types in Go. Go has Zero values, which means it will assign a default value if nothing is initialized to the variables getting declared. Below is a list of some of the types.

Type Values Zero Value Sample value
bool Before first iteration false true
string Before every iteration "" "test"
int 32 or 64 bits integers 0 25
uint 32 or 64 bits unsigned integers 0 5
float32 IEEE-754 32-bit floating-point numbers 0 1.3242
complex64 Complex numbers with float32 real and imaginary parts (0+0i) (2+3i)

I have tried declaring and using all the different types to check the zero values and tried initializing them as well.

package main

import "fmt"

func main() {
    var bZeroValue bool
    var b bool = true
    var sZeroValue string
    var s string = "test" 
    var iZeroValue int
    var i int = -5
    var uZeroValue uint
    var u uint = 5
    var fZeroValue float32
    var f float32 = 3.14
    var cZeroValue complex64
    var c complex64 = (3 + 4i) 
    fmt.Printf("Type: %T Value: %v\n", bZeroValue, bZeroValue)
    fmt.Printf("Type: %T Value: %v\n", b, b)
    fmt.Printf("Type: %T Value: %v\n", sZeroValue, sZeroValue)
    fmt.Printf("Type: %T Value: %v\n", s, s)
    fmt.Printf("Type: %T Value: %v\n", iZeroValue, iZeroValue)
    fmt.Printf("Type: %T Value: %v\n", i, i)
    fmt.Printf("Type: %T Value: %v\n", uZeroValue, uZeroValue)
    fmt.Printf("Type: %T Value: %v\n", u, u)
    fmt.Printf("Type: %T Value: %v\n", fZeroValue, fZeroValue)
    fmt.Printf("Type: %T Value: %v\n", f, f)
    fmt.Printf("Type: %T Value: %v\n", cZeroValue, cZeroValue)
    fmt.Printf("Type: %T Value: %v\n", c, c)
Enter fullscreen mode Exit fullscreen mode

The output shows us the Zero Values and how each value is initialized and used.

Type: bool Value: false
Type: bool Value: true
Type: string Value: 
Type: string Value: test
Type: int Value: 0
Type: int Value: -5
Type: uint Value: 0
Type: uint Value: 5
Type: float32 Value: 0
Type: float32 Value: 3.14
Type: complex64 Value: (0+0i)
Type: complex64 Value: (3+4i)
Enter fullscreen mode Exit fullscreen mode

Go Pointers

Go also has pointers. It holds a memory address the same as C or C++. The type T is the pointer of type T. Zero value of the pointer is nil. We use the *& operator** to generate a pointer.

i := 5
var p *int = &i
Enter fullscreen mode Exit fullscreen mode

We can access value from the pointer using . This is called **dereferencing*.

Enter fullscreen mode Exit fullscreen mode

Go Structs

Structs are also similar to C, they are used to form a collection of typed fields. Typically we can use it to model and maintain the state of an object if we are thinking in OOPS terms.

Below is a short example

type Anime struct {
    name string
    year int

func main(){
    onePiece := Anime("One Piece", 1999)
    fmt.Println(, "was first aired on", onePiece.year)
Enter fullscreen mode Exit fullscreen mode

We access the struct fields using the dot operator.

Go Arrays

Arrays in Go is a collection of the same type of values. The type of values, as well as the length, can't be changed after declaration.

nos := [3]int {1, 2, 3}
Enter fullscreen mode Exit fullscreen mode

But, unlike C, and C++ where arrays are pointers, in Go it is the values. The implication of this difference is 2 fold,

  • It copies the values when we assign the array to a new variable
  • When passing to a function, it passes a copy, not a pointer.

Go Slice

Slice looks and does the same things, but is far more flexible. It can be extended using the built-in append function. Another key difference is that the slice uses a reference. Also, all Go functions use slices rather than arrays.

A simple snippet using slice and extending it with append.

no := []int{1, 2, 3, 4}
no = append(no, 5)
Enter fullscreen mode Exit fullscreen mode

I hope this would help you understand some of the basic types in Go. I hope to make a detailed article on Slice and its internal working in a future article with some examples. In the next article, I will tackle Go routines with the help of a small project.

Happy Coding!

Leave a ❤️ and comment and let me know what you think.
Do you enjoy what you’ve read so far? Consider checking out the article in my site

Top comments (0)

🌚 Friends don't let friends browse without dark mode.

Sorry, it's true.