For-in loop with ranges in Swift

Introduction

A for-in loop with ranges helps you repeat actions a set number of times easily.

When you want to count from 1 to 5 and do something each time.

When you need to repeat a task exactly 10 times.

When you want to go through numbers between two values.

When you want to print numbers in order.

When you want to create a list of numbers using a loop.

Syntax

Swift

for number in start...end {
    // code to repeat
}

The three dots (...) create a closed range including both start and end.

You can also use two dots (..<) for a half-open range that excludes the end.

Examples

This prints numbers 1 through 5, including 5.

Swift

for i in 1...5 {
    print(i)
}

This prints numbers 0, 1, 2 but not 3.

Swift

for i in 0..<3 {
    print(i)
}

This runs the loop once with i equal to 5.

Swift

for i in 5...5 {
    print(i)
}

Sample Program

This program prints a message for each number from 1 to 5.

Swift

for number in 1...5 {
    print("Number is \(number)")
}

Important Notes

Ranges are very useful to control how many times a loop runs.

Using a half-open range (..<) is common when working with arrays to avoid going out of bounds.

Summary

For-in loops with ranges repeat code for each number in the range.

Closed ranges (start...end) include the last number.

Half-open ranges (start..