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Go: Data Types

Prakash Nath Jha's photo
Prakash Nath Jha
·

2 min read

I am following this youtube course link to learn Go programming and will document all the learning in this series of blog posts.

There are different categories of type in Go:

  • Basic type: Numbers, strings, and booleans come under this category.
  • Aggregate type: Array and structs come under this category.
  • Reference type: Pointers, slices, maps, functions, and channels come under this category.
  • Interface type

Types are case-sensitive. Variable type should be known in advance.

Basic data types in Go:

  • string
  • int
  • float
  • complex
  • bool
  • byte

To read more on data types please refer here

Code examples

package main

import "fmt"

func main() {

    // string data type
    var name string = "ben"
    fmt.Println(name)
    fmt.Printf("Variable is of type: %T\n", name)

    // bool data type
    var flag bool = true // false
    fmt.Println(flag)
    fmt.Printf("Variable is of type: %T\n", flag)

    // small int data type
    var sint uint8 = 10 // max val can be 255
    fmt.Println(sint)
    fmt.Printf("Variable is of type: %T\n", sint)

    // int data type
    var int_val int = 10 // max val can be 255
    fmt.Println(int_val)
    fmt.Printf("Variable is of type: %T\n", int_val)

    // float data type
    var float_val float32 = 10.123456789 // max val can be 255
    fmt.Println(float_val)
    fmt.Printf("Variable is of type: %T\n", float_val)

    // default value and type of int
    var int_val_defailt int
    fmt.Println(int_val_defailt)
    fmt.Printf("Variable is of type: %T\n", int_val_defailt)

    // default value for string data type
    var default_str string
    fmt.Printf("Default value of string data type variable is: %s ", default_str)
    fmt.Println()

    // data type can also be inferred implicitly
    var isClosed = false
    fmt.Println(isClosed)
    fmt.Printf("Variable is of type: %T\n", isClosed)

    // we cannot change the data type of a variable
    // isClosed = "hello" will result in compile time

    // no var style using walrun operator
    numUsers := 100
    fmt.Println(numUsers)
    fmt.Printf("Variable is of type: %T\n", numUsers)
    // this operator only works inside a method

    // const variable
    const MOD = 10000
    fmt.Println(MOD)
    fmt.Printf("Variable is of type: %T\n", MOD)
}

Output

ben
Variable is of type: string
true
Variable is of type: bool
10
Variable is of type: uint8
10
Variable is of type: int
10.123457
Variable is of type: float32
0
Variable is of type: int
Default value of string data type variable is:  
false
Variable is of type: bool
100
Variable is of type: int
10000
Variable is of type: int
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