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. String Backslash Escape
  8. Rune
  9. Variable
  10. Zero Value
  11. Constant
  12. If Then Else
  13. Switch/Case
  14. Loop
  15. Basic Types
  16. Array
  17. Slice
  18. Map
  19. Struct
  20. Function
  21. String as Chars
  22. regexp
  23. Read File
  24. Write to File
  25. Walk Dir
  26. Check File Exist
  27. System Call
  28. Get Script Path
  29. Pointer
  30. Defer
  31. Random Number

Examples

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

Reference

  1. Go Spec