Go

go mod init projectname

package main
import ("fmt")

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

run the go file

go run filename.go

If your code is organized into multiple files, you can run the go file with the following command:

go run *.go

make a executable file

go build filename.go

run the executable file

./filename

Variables

var student1 string = "John" //type is string
var student2 = "Jane"        //type is inferred
x := 2                       //type is inferred
const PI = 3.14              //constant
const A int = 1             //constant

Declaring multiple variables

var a, b, c, d int = 1, 3, 5, 7
var a, b = 6, "Hello"
c, d := 7, "World!"

Operators

Arithmetic

Operator	Name	Example
+	Addition	x + y
-	Subtraction	x - y
*	Multiplication	x * y
/	Division	x / y
%	Modulus	x % y
++	Increment	i++
–	Decrement	i--

Assignment

Operator	Example	Same As
=	x = 5	x + y
+=	x += 5	x = x + 5
-=	x -= 5	x = x - 5
*=	x *= 5	x = x * 5
/=	x /= 5	x = x / 5
%=	x %= 5	x = x % 5

Comparison

Operator	Name	Example
==	equal to	x == y
!=	not equal to	x != y
>	greater than	x > y
<	less than	x < y
>=	greater than or equal to	x >= y
<=	less than or equal to	x <= y

Logical

Operator	Name	Description	Example
&&	AND	returns true if both statements are true	x < 5 && x < 10
||	OR	returns true if one of the statements is true	x < 5 || x < 4
!	NOT	reverse the result, returns false if the result is true	!(x < 5 && x < 10)

Lists

Arrays

The size of an array is fixed

var arr1 = [3]int{1,2,3}
arr2 := [5]int{4,5,6,7,8}
var arr3 = [...]int{1,2,3} //length is inferred


arr1[0] = 10 //change value at index 0
fmt.Println(arr1) //output: [10 2 3]

len(arr1)) //length of array (3)

Slices

The size of a slice is dynamic

var myslice1 = []int{}
var slice2 = []int{1,2,3}