The Versatile for Loop

Snippet

The Versatile for Loop

Go has only one loop construct: for. It can operate as a classic three-part for loop, a while-style loop, or an infinite loop with break. The range clause iterates over slices, arrays, maps, and strings with index and value.

snippet.go
go
package main
import "fmt"
 
func main() {
    // Classic counter loop
    for i := 0; i < 3; i++ {
        fmt.Printf("Counter: %d\n", i)
    }
    
    // While-style loop
    count := 3
    for count > 0 {
        fmt.Printf("Countdown: %d\n", count)
        count--
    }
    
    // Infinite loop with break
    sum := 0
    for {
        sum++
        if sum > 5 {
            break
        }
    }
    fmt.Printf("Sum: %d\n", sum)
    
    // Range iteration
    fruits := []string{"apple", "banana", "cherry"}
    for i, fruit := range fruits {
        fmt.Printf("%d: %s\n", i, fruit)
    }
}

Breakdown

for i := 0; i < 3; i++

Classic C-style loop with initialization, condition, and post-statement

for count > 0

While-style: only condition present, loop runs until condition is false

for { sum++; if sum > 5 { break } }

Infinite loop with break for early exit when condition is met

for i, fruit := range fruits

Range returns index and value for each element; use _ to ignore index

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The Versatile for Loop

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