readline()

readline(prompt = NULL)

Returns: character · Updated March 13, 2026 · Base Functions

interactive input base console

readline() reads a line of text from the console (interactive session) or from a connection. It pauses execution until the user enters text and presses Enter. This function is essential for creating interactive R scripts and user prompts.

Syntax

readline(prompt = NULL)

Parameters

Parameter	Type	Default	Description
`prompt`	`character`	`NULL`	A character string to display as the prompt before reading input

Examples

Basic usage

# Interactive prompt for user name
name <- readline("What is your name? ")
# User types: Alice
# Output: "Alice"

# Using the input
paste("Hello,", name)
# Output: "Hello, Alice"

Getting numeric input

# Reading and converting to numeric
age <- readline("Enter your age: ")
age <- as.numeric(age)
# User types: 25
# Output: 25

Multiple prompts in a script

# Creating an interactive data entry workflow
cat("=== New Entry ===\n")
name <- readline("Name: ")
email <- readline("Email: ")
department <- readline("Department: ")

data <- data.frame(
  name = name,
  email = email,
  department = department
)
print(data)

Common Patterns

Input validation: Combine readline() with while loops to validate user input.

get_valid_choice <- function() {
  choice <- readline("Enter 1, 2, or 3: ")
  while (!choice %in% c("1", "2", "3")) {
    choice <- readline("Invalid. Enter 1, 2, or 3: ")
  }
  return(choice)
}

Interactive yes/no prompts:

confirm <- readline("Continue? (y/n): ")
if (tolower(substr(confirm, 1, 1)) == "y") {
  print("Proceeding...")
} else {
  print("Cancelled.")
}