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Working with Ranges in Groovy



Ranges are Lists ( java.util.List ) with sequential values. There are two ways you can define Ranges, using .. this includes the ending value and other way is using ..< which does not include the ending value. Lets see some examples using a Groovy Program

class RangesInGroovy {

	static main(args) {
		
		def rating = 1..5
		println rating // prints [1, 2, 3, 4, 5]
		println rating.from // prints 1
		println rating.to // prints 5
		
		def scale = 1..<10
		println scale // prints [1, 2, 3, 4, 5, 6, 7, 8, 9]
		println scale.from // prints 1
		println scale.to // prints 9
		
	}
}

Ranges are handy to use in for loops

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

(1..5).each {
  println it
}

Another beautiful thing about Ranges is, they can be used in Switch statement, take a look at following program, where the cases are actually ranges which gives the program more readability

class AgeRanges {

	static main(args) {
			
		def input = 15
		
		switch(input) {
			case 0..2 : println 'Infant'; break;
			case 3..12 : println 'Child'; break;
			case 13..59 : println 'Adult'; break;
			case 59..100 : println 'Senior Citizen'; break;
			
			default : println 'NA'
		}
		
	}
}