Swift - Operator Range Operators

Introduction

Swift supports two types of range operators to specify a range of values:

Closed range operator (a...b) specifies a range of values starting from a right up to b (inclusive).

Half-open range operator (a..<b) specifies a range of values starting from a right up to b, but not including b.

To demonstrate how these range operators work, consider the following example:

Demo

//prints 5 to 9 inclusive
for num in 5...9 {
    print(num)// ww w  .  j a  v  a 2 s.c om
}

Result

The preceding code uses the closed range operator to output all the numbers from 5 to 9:

To output only 5 to 8, you can use the half-open range operator:

Demo

//prints 5 to 8
for num in 5..<9 {
    print(num)/*from w w w.j av a  2  s .  c o  m*/
}

Result

The half-open range operator is useful when you are dealing with zero-based lists such as arrays.

The following code snippet is one good example:

Demo

//useful for 0-based lists such as arrays
var fruits = ["apple","orange","pineapple","Json","Database"]
for n in 0..<fruits.count {
    print(fruits[n])/*  ww w.  ja v  a2  s.co m*/
}