Go For Loop – Iterate Efficiently with Range, Conditions & Infinite Loops (2025 Guide)

Introduction – What Is a for Loop in Go?

Go’s for loop is the only looping construct in the language, but it’s incredibly versatile. With it, you can perform traditional counted loops, condition-based loops, infinite loops, and even iterate over collections using range.

In this section, you’ll learn:

• All valid forms of for loops in Go
• How to loop through arrays, slices, maps, and strings using range
• How to break, continue, and control flow inside loops
• Best practices and real-world examples

Basic Syntax – Traditional For Loop

for init; condition; post {
    // block of code
}

Example:

for i := 1; i <= 5; i++ {
    fmt.Println(i)
}

Output:

1
2
3
4
5

While-Style For Loop

Go does not have a while keyword, but the for loop can act like one:

i := 0
for i < 3 {
    fmt.Println(i)
    i++
}

Output:

0
1
2

This behaves exactly like a traditional while loop.

♾️ Infinite Loop

for {
    fmt.Println("Running forever...")
}

Be cautious—use a break to exit when needed.

Loop with range – Iterate Collections

Use range to iterate over arrays, slices, maps, strings, and channels.

Array/Slice:

nums := []int{10, 20, 30}
for i, v := range nums {
    fmt.Printf("Index %d = %d\n", i, v)
}

Output:

Index 0 = 10  
Index 1 = 20  
Index 2 = 30

Map:

m := map[string]int{"a": 1, "b": 2}
for key, val := range m {
    fmt.Printf("%s → %d\n", key, val)
}

String (Unicode-safe):

for i, ch := range "Go" {
    fmt.Printf("%d: %c\n", i, ch)
}

range on strings handles Unicode characters correctly.

Break, Continue, and Label

Break:

for i := 0; i < 10; i++ {
    if i == 5 {
        break
    }
    fmt.Println(i)
}

Stops the loop when i == 5.

Continue:

for i := 1; i <= 5; i++ {
    if i%2 == 0 {
        continue
    }
    fmt.Println(i)
}

Skips even numbers.

Labeled Break (for nested loops):

Outer:
for i := 1; i <= 3; i++ {
    for j := 1; j <= 3; j++ {
        if i*j > 4 {
            break Outer
        }
        fmt.Println(i, j)
    }
}

Exits both loops when condition matches.

Best Practices

Summary – Recap & Next Steps

Go’s for loop is simple yet powerful. Whether you need a basic counter, a while-style condition, or to iterate over collections, the for construct handles it all efficiently and elegantly.

Key Takeaways:

• for is the only loop in Go but supports multiple forms
• Use range for idiomatic iteration over slices, maps, strings, etc.
• Use break, continue, and labels to control loop behavior
• Infinite loops require manual exit conditions

Next: Learn about Go Functions to modularize and reuse logic efficiently.

FAQs – Go For Loop

Is there a while loop in Go?
No. Use for with only a condition: for condition {}

Can I iterate over a string with range?
Yes. It handles Unicode characters properly.

What does range return in a map?
It returns key, value pairs for each map entry.

How can I skip the current iteration?
Use continue to skip to the next loop cycle.

Can I break out of nested loops?
Yes. Use labeled break to exit outer loops.