Java Reference
In-Depth Information
Creating and Naming an ArrayList Object
An object of the class ArrayList is created and named in the same way as any other object,
except that you specify the base type of the ArrayList .
SYNTAX
ArrayList< Base_Type > Object_Name = new ArrayList< Base_Type >();
ArrayList< Base_Type > Object_Name =
new ArrayList< Base_Type >( Initial_Capacity );
The Base_Type must be a reference type, usually a class type; it cannot be a primitive type
such as int or double . When a number is given as an argument to the constructor, that
number determines the initial capacity of the ArrayList .
EXAMPLES
ArrayList<String> list = new ArrayList<String>();
ArrayList<Double> list2 = new ArrayList<Double>(30);
If you would use
String temp = a[index];
for an array of strings a , then the analogous statement for a suitable ArrayList named
list would be
String temp = list.get(index);
Accessing at an Index
If list is an ArrayList , its elements can be accessed as follows:
EXAMPLES
ArrayList<String> list = new ArrayList<String>();
int index;
...
list.set(index, "Here"); //Sets the element
//at index to "Here".
String temp = list.get(index); //The expression
//list.get(index) returns the element at position index.
ArrayList<Integer> list2 = new ArrayList<Integer>();
...
(continued)
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