Golang: if then else

By Xah Lee. Date: . Last updated: .

If

if test { body }

package main

import "fmt"

func main() {

    var x = 3

    if x < 0 {
        fmt.Println("no")
    }

    fmt.Println("yes")

}

Note, there's no parenthesis after the “if”.

If else

if test { body1 } else { body2 }

package main

import "fmt"

func main() {

    var x = 3

    if x < 0 {
        fmt.Printf("no")
    } else {
        fmt.Printf("yes")
    }

}

else if

if test { body1 } else if { body2 } else { body3 }

package main

import "fmt"

func main() {

    var x = 3

    if x < 0 {
        fmt.Println(-1)
    } else if x > 0 {
        fmt.Println(1)
    } else {
        fmt.Println(0)
    }

}

If with a short statement

The if statement can start with a short statement to execute before the condition.

if i := -2; x < i { fmt.Println("no") }

Variables declared by the statement are in scope of the if block and all the else blocks.

package main

import "fmt"

func main() {

    var x = 3

    // if statement can start with a short statement
    if i := -2; x < i {
        fmt.Println("no")
    }

    fmt.Println("yes")

}

ternary if, if expression

There's no “if expression”, such as JavaScript's ( test ? expr1 : expr2 )

Reference

The Go Programming Language Specification - The Go Programming Language#If_statements

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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. Pointer
  22. String as Chars
  23. regexp
  24. Read File
  25. Write to File
  26. Walk Dir
  27. Check File Exist
  28. System Call
  29. Get Script Path
  30. Pointer
  31. Defer
  32. Random Number

Examples

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

Reference

  1. Go Spec