Golang: Random Number

By Xah Lee. Date: .

import "math/rand"

rand.Intn(n) → returns a pseudo random from 0 to n-1, inclusive.

The result is always the same each time you run the program.

package main

import "fmt"
import "math/rand"

func main() {
	for i := 0; i < 30; i++ {
		fmt.Printf("%v", rand.Intn(4))
	}
}

// 133312100023210231123202333023

Set Seed

If you want different result, set a seed.

rand.Seed(n)

package main

import "fmt"
import "math/rand"

func main() {
	rand.Seed(21832)
	for i := 0; i < 30; i++ {
		fmt.Printf("%v", rand.Intn(4))
	}
}

// 003023021103222332330200312311

Random Real Number

For random real number and others, see

https://golang.org/pkg/math/rand/

Cryptography Random Number

For random number that's less predictable, use the package “crypto/rand”

https://golang.org/pkg/crypto/rand/

Reference

https://golang.org/pkg/math/rand/

If you have a question, put $5 at patreon and message me.

Golang

  1. Compile, Run
  2. Source Encoding
  3. Package, Import
  4. Comment
  5. Print
  6. String
  7. Print String
  8. String Backslash Escape
  9. Rune
  10. Variable
  11. Zero Value
  12. Constant
  13. If Then Else
  14. Switch/Case
  15. Loop
  16. Basic Types
  17. Array
  18. Slice
  19. Map
  20. Struct
  21. Function
  22. Closure
  23. Pointer
  24. String, Byte Slice, Rune Slice
  25. regexp
  26. Read File
  27. Write to File
  28. Walk Dir
  29. Check File Exist
  30. System Call
  31. Get Script Path
  32. Defer
  33. Random Number

Examples

  1. Match Any Regexp
  2. Find Replace
  3. Validate Links
  4. Generate Sitemap

Reference

  1. Go Spec