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Apex Loop Statement

 


integer to string in apex program 


You can easily convert an Integer to a String in Apex using the String.valueOf() method. Here's a simple Apex program that demonstrates this conversion:

Integer myInteger = 42; // Replace 42 with your integer value

String myString = String.valueOf(myInteger);


System.debug('Converted String: ' + myString); // Output the converted string to the debug log

Or  

Integer myInteger = 221;

String sInteger = String.valueOf(myInteger);

System.assertEquals('221', sInteger);

List<AccountHistory> ahlist =    [SELECT Id,Name FROM Accounts];

for(AccountHistory ah : ahlist)

 {

  System.debug('Field: ' + ah.Field);

  if (ah.field == 'NumberOfEmployees')

 {

    Integer oldValue = 

      Integer.valueOf(ah.OldValue);

    Integer newValue = 

      Integer.valueOf(ah.NewValue);

}


1. For Loop to Iterate Over a List:


List<String> fruits = new List<String>{'Apple', 'Banana', 'Cherry', 'Date'};


for (String fruit : fruits) {

    System.debug(fruit);

}


2. For Loop to Iterate Over a Set:


Set<Integer> numbers = new Set<Integer>{1, 2, 3, 4, 5};

for (Integer num : numbers) {

    System.debug(num);

}


3. For Loop to Iterate Over a Map:


Map<String, Integer> studentScores = new Map<String, Integer>{

    'Alice' => 95,

    'Bob' => 85,

    'Charlie' => 78

};

for (String name : studentScores.keySet()) {

    Integer score = studentScores.get(name);

    System.debug(name + ': ' + score);

}


4. For Loop for a Set Number of Iterations:


for (Integer i = 0; i < 5; i++) {

    System.debug('Iteration ' + i);

}


1. Add an Element to a List:


You can add an element to the end of a list using the add() method.


List<String> colors = new List<String>{'Red', 'Blue', 'Green'};

colors.add('Yellow');

System.debug(colors); // Outputs: (Red, Blue, Green, Yellow)


2. Remove an Element from a List:

You can remove an element from a list using the remove() method.


List<String> fruits = new List<String>{'Apple', 'Banana', 'Cherry'};

fruits.remove(1); // Removes the element at index 1 (Banana)

System.debug(fruits); // Outputs: (Apple, Cherry)


3. Get an Element by Index:

You can access an element at a specific index using square brackets.

List<Integer> numbers = new List<Integer>{1, 2, 3, 4, 5};

Integer thirdNumber = numbers[2]; // Gets the element at index 2 (3)

System.debug(thirdNumber); // Outputs: 3


4. Check If a List Contains an Element:

You can check if a list contains a specific element using the contains() method.

List<String> names = new List<String>{'Alice', 'Bob', 'Charlie'};

Boolean containsBob = names.contains('Bob');

System.debug(containsBob); // Outputs: true

5. Sort a List:

You can sort a list using the sort() method.


List<Integer> unsortedNumbers = new List<Integer>{5, 1, 4, 3, 2};

unsortedNumbers.sort();

System.debug(unsortedNumbers); // Outputs: (1, 2, 3, 4, 5)


The get() method in Apex is used to access elements in a list or array-like data structure by their index position. The index is a zero-based integer that represents the position of the element within the list. Here's an example of how to use the get() method:

List<String> fruits = new List<String>{'Apple', 'Banana', 'Cherry', 'Date'};

// Access the element at index 1 (second element)

String secondFruit = fruits.get(1);

System.debug(secondFruit); // Outputs: Banana

In Apex, the set() method is used to set the value of a specific element in a list or array-like data structure at a given index position. This allows you to update or modify the content of the list at the specified index. Here's an example of how to use the set() method:


List<String> colors = new List<String>{'Red', 'Blue', 'Green'};

// Set the value at index 1 to 'Yellow'

colors.set(1, 'Yellow');

System.debug(colors); // Outputs: (Red, Yellow, Green)


In Apex, the clear() method is used to remove all elements from a list or collection, effectively making the list empty. This method is particularly useful when you want to clear the contents of a list, making it ready for reuse or for freeing up memory. Here's an example of how to use the clear() method:


List<String> names = new List<String>{'Alice', 'Bob', 'Charlie', 'David'};

System.debug('Original List: ' + names); // Outputs: (Alice, Bob, Charlie, David)

// Clear the list

names.clear();

System.debug('Cleared List: ' + names); // Outputs: ()


Apex variables are Case-Insensitive


Integer m = 100;

for (Integer i = 0; i<10; i++) {

   integer m = 1; //This statement will throw an error as m is being declared

   again

   System.debug('This code will throw error');

}





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