strings: Fast string concatenation using C++

In cheapr: Simple Functions to Save Time and Memory

Fast string concatenation using C++

Description

Fast string concatenation using C++

Usage

paste_(..., sep = "", collapse = NULL, .args = NULL)

Arguments

...	Character vectors to concatenate.
sep	⁠[character(1)]⁠ - A string to separate the supplied strings.
collapse	Optional string to collapse concatenated strings into one string (character vector of length 1).
.args	An alternative to ... so you can supply arguments directly in a list. This is equivalent to do.call(f, .args) but much more efficient.

Examples

library(cheapr)
# Normal usage
paste_("Hello", "and", "Goodbye", sep = " ")
paste_(100, "%")

paste_(letters, LETTERS)
paste_(letters, LETTERS, collapse = "")

# Both concatenating and collapsing
paste_(letters, LETTERS, sep = ",", collapse = " next letter ")
# This is the same as above
paste_(letters, LETTERS, collapse = ", next letter ")

# Recycling with zero-length vectors
paste_("hello", character(), letters)
paste_("hello", character(), letters, collapse = "")

library(bench)

sampled_letters <- sample_(letters, 5e04, TRUE)

# Pasting multiple character vectors
mark(
  paste_(sampled_letters, sep = ","),
  paste(sampled_letters, sep = ","),
  iterations = 50
)
# Collapsing is very fast compared to base R
mark(
  paste_(sampled_letters, collapse = ""),
  paste(sampled_letters, collapse = ""),
  iterations = 50
)

# Concatenating many objects is very fast via `.args`

strings <- sampled_letters |>
  with_local_seed(1) |>
  as.list()

strings <- lapply(strings, rep_len_, 3)

mark(
  paste_(.args = strings),
  do.call(paste0, strings),
  iterations = 15
)
mark(
  paste_(.args = strings, collapse = ""),
  do.call(paste_, c(strings, list(collapse = ""))),
  do.call(paste0, c(strings, list(collapse = ""))),
  iterations = 10
)

cheapr documentation built on Nov. 28, 2025, 5:06 p.m.