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Switch-Case

Sample code link: (https://repl.it/@jjoco/go-switch-case)

Like C-like langauges and TS, Go supports switch-case statements, configured with or without an expression to evaluate cases:

Switch with Expression

Syntax 

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switch expression {
    case x:
        // Do in case x...
    case y:
        // Do in case y...
    case z:
        // Do in case z...
    .
    .
    .
    default:
        //Do when no other case is satisfied ...
}
Syntax notes

  • No break after each case
  • No parentheses around expression

Example: 

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color := "red"

switch color {
    case "green":
        fmt.Println("Go")
    case "yellow":
        fmt.Println("Slow")
    default:
        fmt.Println("Stop")
}

//Output = "Stop"

Switch used as a Long If-Else

Like switch(true) in other languages, using switch in Go without an expression can be used as a cleaner if-else statement, especially with many conditions.

Syntax

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switch {

    case condition1:
    ...
    case condition2:
    ...
    case condition3:
    ...
    .
    .
    .
    default:
    ...
}
Syntax notes:

  • No break after each case
  • No true expression needed in switch

Example 

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grade := 71
letterGrade := ""

switch {
    case grade > 90:
        letterGrade = "A"
    case grade > 80:
        letterGrade = "B"
    case grade > 70:
        letterGrade = "C"
    case grade > 65:
        letterGrade = "D"
    default:
        letterGrade = "F"
}

fmt.Printf("Your grade is %s\n", letterGrade)
//Output = "Your grade is C"