Golang conditionals: Difference between revisions

From wikinotes
Line 60: Line 60:
case 'a' <= letter:
case 'a' <= letter:
     fmt.Println("is a")
     fmt.Println("is a")
}
</syntaxhighlight>
You may also force evaluate sections even if one case is matched with '''falthrough'''.
<syntaxhighlight lang="go">
require "strings"
var  arch      string
var  wordsize  string
cpuarch := "x86-64"
switch {
case strings.HasPrefix(cpuarch, "x86"):
    arch = "x86"
    fallthrough  // <-- continue to next case statement, even when evaluates to true
case strings.Split(cpuarch, "-")[1] == "64":
    wordsize = 64
case
}
}
</syntaxhighlight>
</syntaxhighlight>
</blockquote><!-- Switch Statements -->
</blockquote><!-- Switch Statements -->

Revision as of 00:15, 6 June 2022

If Statements

if 1 > 0 {
    // ...
} else if 2 > 0 {
    // ...
} else {
    // ...
}

Similar to for loops, go's if statements can use an initializer.

if err := file.Chmod(0664); err != nil {
    log.Print(err)
}

// common in hash tests
if _, ok := myMap["someKey"]; ok {
    // eval if key present
}

Short Circuiting

// the final 'false' is never evaluated, because the second is true
if false || true || false { ... }

// same deal with elses
if false {
    // ...
} else if true {
    // ...
} else if false {  // <-- expression never evaluated
    // ...
}

Switch Statements

Regular switch statements that test specific variable

switch var {
case 'a', 'b', 'c':
    fmt.Println("is a, b, or c")
case 'd', 'e', 'f':
    fmt.Println("is d, e, or f")
default:
    fmt.Println("default behaviour")
}

Switch statements can also test different variables

switch {
case '0' <= number:
    fmt.Println("is zero")
case 'a' <= letter:
    fmt.Println("is a")
}

You may also force evaluate sections even if one case is matched with falthrough.

require "strings"

var  arch      string
var  wordsize  string

cpuarch := "x86-64"

switch {
case strings.HasPrefix(cpuarch, "x86"):
    arch = "x86"
    fallthrough   // <-- continue to next case statement, even when evaluates to true
case strings.Split(cpuarch, "-")[1] == "64":
    wordsize = 64
case
}