Apex Beginner Progress | ( Lessons)

Lesson: 01 Lists

List can contain any number of records of primitive, collections, sObjects, user defined and built in Apex type. This is one of the most important type of collection and also, it has some system methods which have been tailored specifically to use with List. List index always starts with 0.

A list should be declared with the keyword 'List'.

List<string> Fruits = new List<string>();
System.debug('Fruits: '+Fruits);

String[] Fruits = new List<String>();

A list with it values can be declared as the following.

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
System.debug('Fruits: '+Fruits);

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
System.debug('The size of the list is: '+Fruits.size());

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
Fruits.add('Mango');
System.debug('The size of the list is: '+Fruits.size());

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
Fruits.add('Mango');
System.debug('The fouth element of the list is: '+Fruits.get(3));

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
Fruits.add('Mango');
System.debug('The fouth element of the list is: '+Fruits[3]);

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
System.debug('The index of the Apple is : '+Fruits.indexOf('Apple'));

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
Fruits.clear();
System.debug('The number of elements of the list is: '+Fruits.size());

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
Fruits.set(2, 'Orange');
System.debug('The second element of the list is: '+Fruits.get(2));

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry', 'Orange'};
Fruits.remove(1);
System.debug('Fruits: '+Fruits);

Apex Code

List<String> Colors = new List<String>
{'Red', 'Blue', 'Orange'};

System.debug(Fruits.contains('Orange'));

Apex Code

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
    for (String i : Fruits) {
      System.debug(i);
    }

Apex Code

1. Way

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
List<string> Fruits2 = new List<String>();
    for (String i : Fruits) {
        
        Fruits2.add(i.toUpperCase());
      
    }
System.debug(Fruits2);

2. Way

List<string> Fruits = new List<string>
{'Banana', 'Apple', 'Cherry'};
    for (String i : Fruits) {
        
        Fruits.set(Fruits.indexof(i), i.toUpperCase());
      
    }
System.debug(Fruits);

Exercises

#	Exercise
1	Sum of the elements of two Lists
2	The greatest element of a List
3	Finding the Maximum Number in a List Using
4	The average of the elements of a List
5	Create a List of Colors
6	Iterate over a List
7	Number Parity Checker
8	Split Full Name into First and Last Name Variables
9	Identifying Even Numbers in a List
10	Email Address List Conversion

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Lesson: 01 Lists

A list should be declared with the keyword 'List'.

A list with it values can be declared as the following.

Apex Code

Apex Beginner