What Is List Array Notation?
Developers comfortable with Array notation can also use it while using Lists. Array and List syntax can be used interchangeably. Array notation is a notation where a list’s elements are referenced by enclosing the index number in square brackets after the list’s name.
Syntax Of List Array Notation
String[] nameList = new String[4];
//or
String[] nameList2 = new List<String>();
//or
List<String> nameList3 = new String[4];
// Set values for 0, 1, 2 indices
nameList[0] = 'Bhavna';
nameList[1] = 'Bhavya';
nameList[2] = 'Swati';
// Size of the list, which is always an integer value
Integer listSize = nameList.size();
// Accessing the 2nd element in the list, denoted by index 1 System.debug(nameList[1]); // ‘Bhavna’
Methods Of List Collection
Some common methods of List collection:
|
Methods |
Definition |
Example |
|
add(element) |
It adds an element to the list. It always adds up at the end. |
List<String> l = new List<String>(); l.add(‘abc’); System.debug(l); //(‘abc’) |
|
size() |
Returns the number of elements in the list. |
l.add(‘def’); System.debug(l.size()); // 2 |
|
get(index) |
Returns the element on the ith index. |
System.debug(l.get(0)); // (‘abc’) |
|
remove(index) |
Removes the element on the ith index. |
l.remove(0); System.debug(l); // (‘abc’) |
|
clone() |
Make a duplicate of a list. |
List<String> l2 = l.clone(); |
|
set() |
Sets the element on the ith position of the list. If there is already a value then the value gets overridden. |
l.add(‘def’); l.add(‘ghi’); System.debug(l); // (‘abc’,‘def’,‘ghi’) l.set(2,’aaa’); System.debug(l); // (‘abc,‘def’,‘aaa’) |
|
sort() |
Sorts the item in ascending order but works with primitive data types only. Returns true if the list is empty. |
l.sort(); System.debug(l); // ( ’aaa’,‘abc’,’def’ ) |
|
isEmpty() |
Sorts the item in ascending order but works with primitive data types only. Returns true if the list is empty. |
System.debug(l.isEmpty()); // false |
|
clear() |
Clears the list. |
l.clear(); |
