countrycode {countrycode}R Documentation

Convert Country Codes

Description

Converts long country names into one of many different coding schemes. Translates from one scheme to another. Converts country name or coding scheme to the official short English country name. Creates a new variable with the name of the continent or region to which each country belongs.

Usage

countrycode(
  sourcevar,
  origin,
  destination,
  warn = TRUE,
  nomatch = NA,
  custom_dict = NULL,
  custom_match = NULL,
  origin_regex = NULL
)

Arguments

sourcevar

Vector which contains the codes or country names to be converted (character or factor)

origin

A string which identifies the coding scheme of origin (e.g., "iso3c"). See codelist for a list of available codes.

destination

A string or vector of strings which identify the coding scheme of destination (e.g., "iso3c" or c("cowc", "iso3c")). See codelist for a list of available codes. When users supply a vector of destination codes, they are used sequentially to fill in missing values not covered by the previous destination code in the vector.

warn

Prints unique elements from sourcevar for which no match was found

nomatch

When countrycode fails to find a match for the code of origin, it fills-in the destination vector with nomatch. The default behavior is to fill non-matching codes with NA. If nomatch = NULL, countrycode tries to use the origin vector to fill-in missing values in the destination vector. nomatch must be either NULL, of length 1, or of the same length as sourcevar.

custom_dict

A data frame which supplies a new dictionary to replace the built-in country code dictionary. Each column contains a different code and must include no duplicates. The data frame format should resemble codelist. Users can pre-assign attributes to this custom dictionary to affect behavior (see Examples section):

  • "origin.regex" attribute: a character vector with the names of columns containing regular expressions.

  • "origin.valid" attribute: a character vector with the names of columns that are accepted as valid origin codes.

custom_match

A named vector which supplies custom origin and destination matches that will supercede any matching default result. The name of each element will be used as the origin code, and the value of each element will be used as the destination code.

origin_regex

NULL or Logical: When using a custom dictionary, if TRUE then the origin codes will be matched as regex, if FALSE they will be matched exactly. When NULL, countrycode will behave as TRUE if the origin name is in the custom_dictionary's origin_regex attribute, and FALSE otherwise. See examples section below.

Note

For a complete description of available country codes and languages, please see the documentation for the codelist conversion dictionary.

Panel data (i.e., country-year) can pose particular problems when converting codes. For instance, some countries like Vietnam or Serbia go through political transitions that justify changing codes over time. This can pose problems when using codes from organizations like CoW or Polity IV, which produce codes in country-year format. Instead of converting codes using countrycode(), we recommend that users use the codelist_panel data.frame as a base into which they can merge their other data. This data.frame includes most relevant code, and is already "reconciled" to ensure that each political unit is only represented by one row in any given year. From there, it is just a matter of using merge() to combine different datasets which use different codes.

Examples

library(countrycode)

# ISO to Correlates of War
countrycode(c('USA', 'DZA'), origin = 'iso3c', destination = 'cown')

# English to ISO
countrycode('Albania', origin = 'country.name', destination = 'iso3c')

# German to French
countrycode('Albanien', origin = 'country.name.de', destination = 'iso.name.fr')

# Using custom_match to supercede default codes
countrycode(c('United States', 'Algeria'), 'country.name', 'iso3c')
countrycode(c('United States', 'Algeria'), 'country.name', 'iso3c',
            custom_match = c('Algeria' = 'ALG'))

## Not run: 
 # Download the dictionary of US states from Github
 state_dict <- "https://bit.ly/2ToSrFv"
 state_dict <- read.csv(state_dict)

 # The "state.regex" column includes regular expressions, so we set an attribute.
 attr(state_dict, "origin_regex") <- "state.regex"
 countrycode(c('AL', 'AK'), 'abbreviation', 'state',
             custom_dict = state_dict)
 countrycode(c('Alabama', 'North Dakota'), 'state.regex', 'state',
             custom_dict = state_dict)

## End(Not run)

[Package countrycode version 1.3.0 Index]