I've been working lately with some students running cross-country regressions, and it struck me it would be nice to have a convenient way to map between country names and the two- or three-letter codes for countries -- the former are often found in cross-country data files but the latter are generally more usable in plots. So we now (in git and snapshots) have a function, isocountry(), to do that job using the ISO 3166 country information. We handle three elements from ISO 3166: 1 Country name 2 2-letter code 3 3-letter code The basic idea is that we take one of these as input and return one of the others (or the same one, see below) as output. The function (not yet formally documented) takes two arguments: * A string, or array of strings (required) * An integer (optional, may be omitted) It returns either a string or an array of strings, matching the type of the first argument. The second argument (1, 2, or 3), if supplied, says which of the three forms above you want on output. If the optional argument is omitted the default is to convert from 1 to 2 (if form 1 is given on input), or 2 to 1 (if 2 is given), or 3 to 1. If input is given that is neither two nor three upper-case characters we try to interpret it as part of a full country name. In that case we try to return the country's 2-letter code, but a second argument of 1 can be given to return the full name (if a partial match is found). Here are some examples: <gretl> ? eval isocountry("Bolivia") BO ? eval isocountry("Bolivia", 3) BOL ? eval isocountry("GB") United Kingdom of Great Britain and Northern Ireland ? eval isocountry("GB", 3) GBR # try some abbreviations ? eval isocountry("Vanua") VU ? eval isocountry("Zimb") ZW ? eval isocountry("Zim", 1) Zimbabwe ? eval isocountry("Wurzistan") isocountry: 'Wurzistan' was not matched ? strings S = defarray("ES", "DE", "SD") ? strings C = isocountry(S) ? print C Array of strings, length 3 [1] "Spain" [2] "Germany" [3] "Sudan" ? C = isocountry(S, 3) ? print C Array of strings, length 3 [1] "ESP" [2] "DEU" [3] "SDN" </gretl> This is implemented as a "plugin", so the ISO 3166 table is not bloating gretl's memory footprint unless you have reason to use it. Comments welcome, if anyone has ideas for making this more useful. Allin