by Matthew Barlowe⌗

This is a tutorial going over the syntax of loops in R. If you want a break down of how loops work and the philosophy please read my Python loop tutorial. Loops should be a last resort in R as they are slow and inefficient. Often you can do what you need to in loops using the apply family of functions or the purrr package.

for loops⌗

for (i in 1:10) {
    print(paste("Your number is", i))
}

some_numbers <- c(1,3,5,3,0,10,35)

for (i in some_numbers) {
    print(paste("Your number is", i))
}

while loops⌗

answer <- readline(prompt="What's the best part about Matt? ")
while (answer != 'He's Awesome") {
    print("Sorry, that isn't the correct answer.")
    answer <- readline(prompt='')
}

repeat loops⌗

These loops aren’t present in Python. repeat loops are similar to while loops except that repeat loops require the user to explicitly break the loop when the condition is met instead of doing it automatically like while loops. Here is the example above rewritten as a repeat loop.

answer <- readline(prompt="What's the best part about Matt? ")
repeat {
    if(answer == "He's Aweseome"){
        break
    }
    print("Sorry, that isn't the correct answer.")
    answer <- readline(prompt='')
}

Sources⌗

While vs. Repeat Loops in R

I hate linking to this because it’s Datacamp but it’s free so hopefully they aren’t making money off it

Tutorial on Loops in R