Groovy - Lists


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The List is a structure used to store a collection of data items. In Groovy, the List holds a sequence of object references. Object references in a List occupy a position in the sequence and are distinguished by an integer index. A List literal is presented as a series of objects separated by commas and enclosed in square brackets.

To process the data in a list, we must be able to access individual elements. Groovy Lists are indexed using the indexing operator []. List indices start at zero, which refers to the first element.

Following are some example of lists −

  • [11, 12, 13, 14] – A list of integer values
  • [‘Angular’, ‘Groovy’, ‘Java’] – A list of Strings
  • [1, 2, [3, 4], 5] – A nested list
  • [‘Groovy’, 21, 2.11] – A heterogeneous list of object references
  • [ ] – An empty list

In this chapter, we will discuss the list methods available in Groovy.

S.No. Methods & Description
1 add()

Append the new value to the end of this List.

2 contains()

Returns true if this List contains the specified value.

3 get()

Returns the element at the specified position in this List.

4 isEmpty()

Returns true if this List contains no elements

5 minus()

Creates a new List composed of the elements of the original without those specified in the collection.

6 plus()

Creates a new List composed of the elements of the original together with those specified in the collection.

7 pop()

Removes the last item from this List

8 remove()

Removes the element at the specified position in this List.

9 reverse()

Create a new List that is the reverse the elements of the original List

10 size()

Obtains the number of elements in this List.

11 sort()

Returns a sorted copy of the original List.



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