Loops

A loop is used to repeat some operation a multiple number of times. In R, there are while and for loops.

While Loop

The statement(s) within a while loop code block will continue to execute as long as a declared condition is TRUE.

The following example will continuously execute the statements within the while loop block until the condition is no longer TRUE:

var1 <- 0

while (var1 < 100) {
  print(var1)
  var1 <- var1 + 1
}

For Loop

The statement(s) within a for loop code block will execute once for each item in a list-like data structure like a vector or list.

The following example will execute the statement within the for loop block for each item in the list:

NY <- list("Bronx", "Brooklyn", "Manhattan", "Queens", "Staten Island")

for (borough in NY) {
  print(borough)
}

Additional control flow statements can be used within these blocks for both types of loops.