Groovy: Lists

List is an ordered collection of elements.

How to specify a list?

List can be created using [].

HelloWorld.groovy

primes = [2, 3, 5, 7]

println "size : ${primes.size()}"

for(i in primes){
 print i + " "
}

Output

size : 4

2 3 5 7

By default, Groovy create the instance of ArrayList, you can confirm the same using below program.

HelloWorld.groovy

primes = [2, 3, 5, 7]
println "\nclass : ${primes.class.name}"

Output

class : java.util.ArrayList

Create a list from range of elements

Using toList() method, you can create a list from range of elements.

HelloWorld.groovy

ints = (1..10).toList()

for(i in ints){
 println i
}

Output

1

2

3

4

5

6

7

8

9

10

You can add the elements to the list using index notation.

HelloWorld.groovy

primes = [2, 3, 5, 7]

primes[5] = 13

for(i in primes){
 println i
}

Output

2

3

5

7

null

13

As you observe the output, primes[5] is set with the value 13 and primes[4] is set with the value null.

Previous                                                 Next                                                 Home