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Loops (for, while, repeat)
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Loops in R are used to repeat a block of code multiple times. They are useful when you need to perform the same operation on many values, such as processing elements of a vector, calculating results for a sequence of numbers, or running a task until a certain condition is met. Loops help reduce repetition in code and make programs more efficient.
The for loop is used when you know in advance how many times you want the loop to run. It is commonly used to iterate over a sequence of numbers or elements in a vector. For example, if you want to print numbers from 1 to 5, a for loop will take each number one by one and execute the code inside the loop. The loop continues until it reaches the last value in the sequence. This type of loop is very useful for tasks like summing values, printing lists, or applying the same calculation to each element.
The while loop is used when the number of repetitions is not known in advance. Instead of running a fixed number of times, the while loop continues to run as long as a specified condition is true. For example, you can start with a number x <- 1 and use a while loop to keep increasing it until it becomes greater than 5. As long as the condition x <= 5 is true, the loop will continue to execute. Once the condition becomes false, the loop stops. While loops are useful when the stopping point depends on a condition rather than a fixed count.
The repeat loop is similar to the while loop, but it runs indefinitely until you explicitly stop it using a break statement. The repeat loop does not check a condition at the beginning. Instead, it keeps running the code until a break condition is reached inside the loop. For example, you can start with a number and keep increasing it inside a repeat loop. When the number becomes greater than a certain value, you use the break statement to stop the loop. This type of loop is useful when the exit condition needs to be checked after the loop has started.
Loops are important in R because they allow you to automate repetitive tasks, process large datasets, and control program execution based on conditions. Understanding for, while, and repeat loops helps you write more flexible and powerful R programs.
