Learn Java for Web Development

410 APPENDIX B: Introduction to Groovy

Arrays

A Groovy array is a sequence of objects, just like a Java array (see Listing B-17).

Listing B-17. Creating and Using Arrays

1. def stringArray = new String[3]


2. stringArray[0] = "A"


3. stringArray[1] = "B"


4. stringArray[2] = "C"


5. println stringArray


6. println stringArray[0]


7. stringArray.each { println it}


8. println stringArray[-1..-3]

   Line 1 creates a string array of size 3.

   Lines 2 to 4 use an index to access the array.

   Line 7 illustrates using the each() method to iterate through the array. The

each() method is used to iterate through and apply the closure on every

element.

   Line 8 shows something interesting—it uses a range, which will be discussed

shortly, to access the array.

[A, B, C]

A

A

B

C

[C, B, A]

Lists

A Groovy list is an ordered collection of objects, just as in Java. It is an implementation of the
java.util.List interface. Listing B-18 illustrates how to create a list and common usages.

Listing B-18. Creating and Using Lists

1. def emptyList = []


2. def list = ["A"]


3. list.add "B"


4. list.add "C"


5. list.each { println it }


6. println list[0]


7. list.set(0, "Vishal")


8. println list.get(0)


9. list.remove 2


10. list.each { println it }