R Break and Next

How it works

next skips the rest of the current iteration. break exits the nearest loop. A repeat loop has no condition at its header, so a break or another terminating action is essential. Use these controls where they make a bounded algorithm clearer, not to conceal an unexplained early exit.

Run this R example

These examples run locally with R, not PHP, Python or JavaScript. The reviewed baseline is R 4.5.2 on Windows x64/UCRT, using only packages shipped with R. This is a tested version, not a newest-release claim. Install your own R from the official R project; an IDE is optional. Save the complete source as loop-control.R in a separate learning folder and run Rscript --vanilla loop-control.R. Keep code and fictional fixtures separate from a real project.

Bhylu has no R browser runner. There is no Try in playground link because the existing Python and JavaScript editors do not execute R. No package installation, account, network dataset, Apache, MySQL or PHP setting is needed to run these base-R sources.

The complete download uses a local scope, restores its temporary options and treats unexpected warnings as errors. Examples that handle an expected warning do so narrowly. Random examples change only their R process’s RNG state. File examples own their temporary output; figure examples leave their named PNG in the current learning folder and refuse to overwrite it. Use a new empty folder to rerun a figure.

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Example

local({
  previous_options <- options(warn = 2, digits = 8, stringsAsFactors = FALSE)
  on.exit(options(previous_options), add = TRUE)
  kept <- integer(0)
  for (n in 1:6) {
    if (n == 2L) next
    if (n == 5L) break
    kept <- c(kept, n)
  }
  cat("kept:", paste(kept, collapse = ", "), "\n")
  steps <- 0L
  repeat {
    steps <- steps + 1L
    if (steps >= 3L) break
  }
  cat("repeat steps:", steps, "\n")
  invisible(NULL)
})

kept <- integer(0)
for (n in 1:6) {
  if (n == 2L) next
  if (n == 5L) break
  kept <- c(kept, n)
}
cat("kept:", paste(kept, collapse = ", "), "\n")
steps <- 0L
repeat {
  steps <- steps + 1L
  if (steps >= 3L) break
}
cat("repeat steps:", steps, "\n")

Expected result

kept: 1, 3, 4
repeat steps: 3

Two is skipped and reaching five stops the for loop before five is added. The repeat loop has its own explicit three-step limit. A break inside nested loops exits only the nearest loop, so document which work remains.