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. |
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