R: Convert Roman Numerals to Integers

roman2int {gtools} | R Documentation

## Convert Roman Numerals to Integers

### Description

Convert roman numerals to integers

### Usage

    roman2int(roman)

### Arguments

`roman` | character vector containing roman numerals

### Details

This function will convert roman numerals to integers without the upper bound imposed by R (3899), ignoring case.

### Value

A integer vector with the same length as `roman`. Character strings which are not valid roman numerals will be converted to `NA`.

### Author(s)

Gregory R. Warnes greg@warnes.net

### See Also

`as.roman`

### Examples

    roman2int(c("I", "V", "X", "C", "L", "D", "M"))

    # works regardless of case
    roman2int("MMXVI")
    roman2int("mmxvi")

    # works beyond R's limit of 3899
    val.3899 <- "MMMDCCCXCIX"
    val.3900 <- "MMMCM"
    val.4000 <- "MMMM"
    as.numeric(as.roman(val.3899))
    as.numeric(as.roman(val.3900))
    as.numeric(as.roman(val.4000))

    roman2int(val.3899)
    roman2int(val.3900)
    roman2int(val.4000)

[Package gtools version 3.9.2.2 Index]