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Data Types
Go is statically typed, meaning variables always have a specific type and that type cannot change.
Data Type for a variable defines:
- The amount of memory space allocated for variables.
- A data type specifies the possible values for variables.
- The operations that can be performed on variables.
Go built-in data types:
- Numbers
- Boolean
- String
Type | Size | Description (Two's complement) |
int8 | 8 bits | 8 bit signed integer |
int16 | 16 bits | 16 bit signed integer |
int32 | 32 bits | 32 bit signed integer |
int64 | 64 bits | 64 bit signed integer, can also be represented in octal and hexadecimal |
int | Platform dependent | signed integers of at least 32-bit in size, not equivalent to int32. |
Type | Size | Description (Two's complement) |
uint8 | 8 bits | 8 bit unsigned integer |
uint16 | 16 bits | 16 bit unsigned integer |
uint32 | 32 bits | 32 bit unsigned integer |
uint64 | 64 bits | 64 bit unsigned integer |
uint | Platform dependent | unsigned integers of at least 32-bit in size, not equivalent to int32. |
Use int unless for specific reasons for others. Integral types have default value of 0. Octal numbers can be declared using prefix and hexadecimal using the 0x prefix.
Type | Description (Two's complement) |
byte | It is alias for and equivalent to uint8 |
rune | It is alias for and equivalent to int32, used to represent characters. |
uintptr | It is used to hold memory address pointers |
Golang does not support a char data type, instead it has byte and rune to represent character values. This helps to distinguish characters from integer values. byte data type is represented with a ASCII value and the rune data type is represented with Unicode value encoded in UTF-8 format.
package main
import "fmt"
func main() {
var varByte byte = 'a' // ASCII value of 97
var varRune rune = '♥' // Unicode value of U+2665
fmt.Printf("%c = %d and %c = %U\n", varByte, varByte, varRune, varRune)
}
a = 97 and ♥ = U+2665
Go supports float32 and float64 represented with 32-bit and 64-bit in memory respectively.
var num1 float32 = 20.0320
var num2 = 20.0818 // Type inferred as float64
Go supports complex64 and complex128. Each of the type uses float32 and float64 respectively, to represent their real and imaginary parts.
var num1 = 3 + 7i // Type inferred as complex128
var flag = true
// No newlines, and can contain escape sequences like \n, \t
var fstr="Hello World"
// Can span multiple lines. Escape characters are not allowed.
var sstr= `Hello world, this
a multi-line text string.`
var i int = 42
var f float64 = float64(i)
var u uint = uint(f)
// short syntax
i := 42
f := float64(i) // 42.000000
u := uint(f)
When declaring a variable without specifying an explicit type (either by using the
:= syntax or var = expression syntax), the variable's type is inferred from the value on the right hand side.package main
import "fmt"
func main() {
i := 42
f := 12.0212
c := 0.5 + 2i
fmt.Printf("i is of type %T\n", i)
fmt.Printf("f is of type %T\n", f)
fmt.Printf("c is of type %T\n", c)
}
i is of type int
f is of type float64
c is of type complex128
Last modified 2yr ago