An illustration of a for loop in R

control_flow_loop.R

a <- 1:3
b <- 4:6

# Loop over every element in a and print the result of the i-th elememt of a plus 10
for (i in seq_along(a)){
  print(i + 10)
}

[1] 11
[1] 12
[1] 13

# Nest for loops to multiply the i-th element of a with the j-th element of b
for (i in seq_along(a)){
  for (j in seq_along((b))){
    print(paste0(a[i], " times ", b[j], " equals ", a[i] * b[j]))
  }
}

[1] "1 times 4 equals 4"
[1] "1 times 5 equals 5"
[1] "1 times 6 equals 6"
[1] "2 times 4 equals 8"
[1] "2 times 5 equals 10"
[1] "2 times 6 equals 12"
[1] "3 times 4 equals 12"
[1] "3 times 5 equals 15"
[1] "3 times 6 equals 18"