Asks the user for a row number from a data.frame table

The function gets a data.frame and asks the user to choose a row number. Once choosen, that row number is returned from the function.

ask.user.for.a.row(
  TABLE,
  header_text = "Possible versions to download (choose one)",
  questions_text
)

Arguments

TABLE	a data.frame table with rows from which we wish the user to choose a row. If TABLE is not a data.frame, it will be coerced into one.
header_text	the text the users sees (often a question) as a title for the printed table - explaining which row he should choose from
questions_text	the question the users see after the printing of the table - explaining which row he should choose from. (the default is: "Please review the table of versions from above, and enter the row number of the file-version you'd like to install: ")

Source

On how to ask the user for input:

https://stackoverflow.com/questions/5974967/what-is-the-correct-way-to-ask-for-user-input-in-an-r-program

Value

The row number the user has choosen from the data.frame table.

Details

This function is used in installr when we are not sure what version of the software to download, or when various actions are available for the user to choose from. If the user doesn't give a valid row number, the function repeats its questions until a valid row number is chosen (or the user escapes)

Examples

if (FALSE) {
version_table <- data.frame(versions = c("devel", "V 1.0.0", "V 2.0.0"))
installr:::ask.user.for.a.row(version_table)
}