In Apex, you can use loops to iterate over collections, execute a block of code multiple times, or perform repetitive tasks. There are mainly three types of loops in Apex: for loop, while loop, and do-while loop. Here are examples of each:
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1- For Loop:
The for loop is commonly used when the number of iterations is known.
for (Integer i = 1; i <= 5; i++) {
System.debug('Iteration ' + i);
}
This loop will iterate from 1 to 5, and the System.debug statement will display each iteration.
2- While Loop:
The while loop is useful when the number of iterations is not known beforehand.
Integer j = 1;
while (j <= 5) {
System.debug('Iteration ' + j);
j++;
}
This loop will also iterate from 1 to 5, and the System.debug statement will be executed in each iteration.
3- Do-While Loop:
Similar to the while loop, the do-while loop is used when you want to execute the loop body at least once, regardless of the loop condition.
Integer k = 1;
do {
System.debug('Iteration ' + k);
k++;
} while (k <= 5);
This loop will iterate from 1 to 5, and the System.debug statement will be executed at least once.
Looping Through Lists:
You can also use loops to iterate through collections like lists or arrays.
List fruits = new List{'Apple', 'Orange', 'Banana'};
for (String fruit : fruits) {
System.debug('Fruit: ' + fruit);
}
This loop iterates through each element in the fruits list and prints each fruit.
Thank,s..
Raghvendra Pratap Singh Apex Developer