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.

Sr.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.