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GO

Variables

Long Notation

var foo int = 9
var bar string = "Hello World"
var arg bool = true

Var (
    myint int = 1
    mystring string = "hello"
    mybool bool = false
)

Short Notation

foo := 9
bar := "Hello World"
arg := true

foo, bar, arg := 9, "Hello World", true

Operators

Most numeric operators are just like you would expect. You can use the "+" operator to concatenate strings 

package main 
import "fmt" 
func main() {
    givenName := "John"
    familyName := "Smith"
    fullName := givenName + " " + familyName
    fmt.Println("Hello,", fullName) }

Shorthand Operators

Note that the add/subtract and assign operators work with numeric variables as well as stirngs - -- Reduce a number by 1 - ++ Increase a number by 1 - += Add and assign - -= Subtract and assign

Logical Operators

Comparison

  • == True if two values are the same
  • != True if two values are not the same
  • < True if the left value is less than the right value
  • <= True if the left value is less or equal to the right value
  • > True if the left value is greater than the right value
  • >= True if the left value is greater than or equal to the right value

Logical Operators

  • && True if the left and right values are both true
  • || True if one or both the left and right values are true
  • ! This operator only works with a single value and results in true if the value is false

Zero Values

Each data type has a zero value. - Booleans: false - Numbers: 0 - Strings: "" (empty string) - pointers, functions, interfaces, slices, channels, maps: nil

Pointers

Declaring a pointer 1) declare a pointer, has the value of nil 

var foo *int
2) create a new memory address 
foo := new(int)
3) create a pointer to an existing variable 
var foo int = 4
var bar = &foo

De-referencing Pointer

[!warning] It is best practice to make sure the pointer is not null before you try to get the pointer's value

Functions with Pointers