Ruby. Array of countries with their codes. According to ISO 3166-1 alpha-2 (two-letter codes). Based on https://gist.github.com/vxnick/380904

Ruby list of countries with their codes ISO 3166-1 alpha-2.rb

[{:name=>"Afghanistan", :code=>"AF"},
 {:name=>"Aland Islands", :code=>"AX"},
 {:name=>"Albania", :code=>"AL"},
 {:name=>"Algeria", :code=>"DZ"},
 {:name=>"American Samoa", :code=>"AS"},
 {:name=>"Andorra", :code=>"AD"},
 {:name=>"Angola", :code=>"AO"},
 {:name=>"Anguilla", :code=>"AI"},
 {:name=>"Antarctica", :code=>"AQ"},
 {:name=>"Antigua And Barbuda", :code=>"AG"},
 {:name=>"Argentina", :code=>"AR"},
 {:name=>"Armenia", :code=>"AM"},
 {:name=>"Aruba", :code=>"AW"},
 {:name=>"Australia", :code=>"AU"},
 {:name=>"Austria", :code=>"AT"},
 {:name=>"Azerbaijan", :code=>"AZ"},
 {:name=>"Bahamas", :code=>"BS"},
 {:name=>"Bahrain", :code=>"BH"},
 {:name=>"Bangladesh", :code=>"BD"},
 {:name=>"Barbados", :code=>"BB"},
 {:name=>"Belarus", :code=>"BY"},
 {:name=>"Belgium", :code=>"BE"},
 {:name=>"Belize", :code=>"BZ"},
 {:name=>"Benin", :code=>"BJ"},
 {:name=>"Bermuda", :code=>"BM"},
 {:name=>"Bhutan", :code=>"BT"},
 {:name=>"Bolivia", :code=>"BO"},
 {:name=>"Bosnia And Herzegovina", :code=>"BA"},
 {:name=>"Botswana", :code=>"BW"},
 {:name=>"Bouvet Island", :code=>"BV"},
 {:name=>"Brazil", :code=>"BR"},
 {:name=>"British Indian Ocean Territory", :code=>"IO"},
 {:name=>"Brunei Darussalam", :code=>"BN"},
 {:name=>"Bulgaria", :code=>"BG"},
 {:name=>"Burkina Faso", :code=>"BF"},
 {:name=>"Burundi", :code=>"BI"},
 {:name=>"Cambodia", :code=>"KH"},
 {:name=>"Cameroon", :code=>"CM"},
 {:name=>"Canada", :code=>"CA"},
 {:name=>"Cape Verde", :code=>"CV"},
 {:name=>"Cayman Islands", :code=>"KY"},
 {:name=>"Central African Republic", :code=>"CF"},
 {:name=>"Chad", :code=>"TD"},
 {:name=>"Chile", :code=>"CL"},
 {:name=>"China", :code=>"CN"},
 {:name=>"Christmas Island", :code=>"CX"},
 {:name=>"Cocos (Keeling) Islands", :code=>"CC"},
 {:name=>"Colombia", :code=>"CO"},
 {:name=>"Comoros", :code=>"KM"},
 {:name=>"Congo", :code=>"CG"},
 {:name=>"Congo, Democratic Republic", :code=>"CD"},
 {:name=>"Cook Islands", :code=>"CK"},
 {:name=>"Costa Rica", :code=>"CR"},
 {:name=>"Cote D'Ivoire", :code=>"CI"},
 {:name=>"Croatia", :code=>"HR"},
 {:name=>"Cuba", :code=>"CU"},
 {:name=>"Cyprus", :code=>"CY"},
 {:name=>"Czech Republic", :code=>"CZ"},
 {:name=>"Denmark", :code=>"DK"},
 {:name=>"Djibouti", :code=>"DJ"},
 {:name=>"Dominica", :code=>"DM"},
 {:name=>"Dominican Republic", :code=>"DO"},
 {:name=>"Ecuador", :code=>"EC"},
 {:name=>"Egypt", :code=>"EG"},
 {:name=>"El Salvador", :code=>"SV"},
 {:name=>"Equatorial Guinea", :code=>"GQ"},
 {:name=>"Eritrea", :code=>"ER"},
 {:name=>"Estonia", :code=>"EE"},
 {:name=>"Ethiopia", :code=>"ET"},
 {:name=>"Falkland Islands (Malvinas)", :code=>"FK"},
 {:name=>"Faroe Islands", :code=>"FO"},
 {:name=>"Fiji", :code=>"FJ"},
 {:name=>"Finland", :code=>"FI"},
 {:name=>"France", :code=>"FR"},
 {:name=>"French Guiana", :code=>"GF"},
 {:name=>"French Polynesia", :code=>"PF"},
 {:name=>"French Southern Territories", :code=>"TF"},
 {:name=>"Gabon", :code=>"GA"},
 {:name=>"Gambia", :code=>"GM"},
 {:name=>"Georgia", :code=>"GE"},
 {:name=>"Germany", :code=>"DE"},
 {:name=>"Ghana", :code=>"GH"},
 {:name=>"Gibraltar", :code=>"GI"},
 {:name=>"Greece", :code=>"GR"},
 {:name=>"Greenland", :code=>"GL"},
 {:name=>"Grenada", :code=>"GD"},
 {:name=>"Guadeloupe", :code=>"GP"},
 {:name=>"Guam", :code=>"GU"},
 {:name=>"Guatemala", :code=>"GT"},
 {:name=>"Guernsey", :code=>"GG"},
 {:name=>"Guinea", :code=>"GN"},
 {:name=>"Guinea-Bissau", :code=>"GW"},
 {:name=>"Guyana", :code=>"GY"},
 {:name=>"Haiti", :code=>"HT"},
 {:name=>"Heard Island & Mcdonald Islands", :code=>"HM"},
 {:name=>"Holy See (Vatican City State)", :code=>"VA"},
 {:name=>"Honduras", :code=>"HN"},
 {:name=>"Hong Kong", :code=>"HK"},
 {:name=>"Hungary", :code=>"HU"},
 {:name=>"Iceland", :code=>"IS"},
 {:name=>"India", :code=>"IN"},
 {:name=>"Indonesia", :code=>"ID"},
 {:name=>"Iran, Islamic Republic Of", :code=>"IR"},
 {:name=>"Iraq", :code=>"IQ"},
 {:name=>"Ireland", :code=>"IE"},
 {:name=>"Isle Of Man", :code=>"IM"},
 {:name=>"Israel", :code=>"IL"},
 {:name=>"Italy", :code=>"IT"},
 {:name=>"Jamaica", :code=>"JM"},
 {:name=>"Japan", :code=>"JP"},
 {:name=>"Jersey", :code=>"JE"},
 {:name=>"Jordan", :code=>"JO"},
 {:name=>"Kazakhstan", :code=>"KZ"},
 {:name=>"Kenya", :code=>"KE"},
 {:name=>"Kiribati", :code=>"KI"},
 {:name=>"Korea", :code=>"KR"},
 {:name=>"Kuwait", :code=>"KW"},
 {:name=>"Kyrgyzstan", :code=>"KG"},
 {:name=>"Lao People's Democratic Republic", :code=>"LA"},
 {:name=>"Latvia", :code=>"LV"},
 {:name=>"Lebanon", :code=>"LB"},
 {:name=>"Lesotho", :code=>"LS"},
 {:name=>"Liberia", :code=>"LR"},
 {:name=>"Libyan Arab Jamahiriya", :code=>"LY"},
 {:name=>"Liechtenstein", :code=>"LI"},
 {:name=>"Lithuania", :code=>"LT"},
 {:name=>"Luxembourg", :code=>"LU"},
 {:name=>"Macao", :code=>"MO"},
 {:name=>"Macedonia", :code=>"MK"},
 {:name=>"Madagascar", :code=>"MG"},
 {:name=>"Malawi", :code=>"MW"},
 {:name=>"Malaysia", :code=>"MY"},
 {:name=>"Maldives", :code=>"MV"},
 {:name=>"Mali", :code=>"ML"},
 {:name=>"Malta", :code=>"MT"},
 {:name=>"Marshall Islands", :code=>"MH"},
 {:name=>"Martinique", :code=>"MQ"},
 {:name=>"Mauritania", :code=>"MR"},
 {:name=>"Mauritius", :code=>"MU"},
 {:name=>"Mayotte", :code=>"YT"},
 {:name=>"Mexico", :code=>"MX"},
 {:name=>"Micronesia, Federated States Of", :code=>"FM"},
 {:name=>"Moldova", :code=>"MD"},
 {:name=>"Monaco", :code=>"MC"},
 {:name=>"Mongolia", :code=>"MN"},
 {:name=>"Montenegro", :code=>"ME"},
 {:name=>"Montserrat", :code=>"MS"},
 {:name=>"Morocco", :code=>"MA"},
 {:name=>"Mozambique", :code=>"MZ"},
 {:name=>"Myanmar", :code=>"MM"},
 {:name=>"Namibia", :code=>"NA"},
 {:name=>"Nauru", :code=>"NR"},
 {:name=>"Nepal", :code=>"NP"},
 {:name=>"Netherlands", :code=>"NL"},
 {:name=>"Netherlands Antilles", :code=>"AN"},
 {:name=>"New Caledonia", :code=>"NC"},
 {:name=>"New Zealand", :code=>"NZ"},
 {:name=>"Nicaragua", :code=>"NI"},
 {:name=>"Niger", :code=>"NE"},
 {:name=>"Nigeria", :code=>"NG"},
 {:name=>"Niue", :code=>"NU"},
 {:name=>"Norfolk Island", :code=>"NF"},
 {:name=>"Northern Mariana Islands", :code=>"MP"},
 {:name=>"Norway", :code=>"NO"},
 {:name=>"Oman", :code=>"OM"},
 {:name=>"Pakistan", :code=>"PK"},
 {:name=>"Palau", :code=>"PW"},
 {:name=>"Palestinian Territory, Occupied", :code=>"PS"},
 {:name=>"Panama", :code=>"PA"},
 {:name=>"Papua New Guinea", :code=>"PG"},
 {:name=>"Paraguay", :code=>"PY"},
 {:name=>"Peru", :code=>"PE"},
 {:name=>"Philippines", :code=>"PH"},
 {:name=>"Pitcairn", :code=>"PN"},
 {:name=>"Poland", :code=>"PL"},
 {:name=>"Portugal", :code=>"PT"},
 {:name=>"Puerto Rico", :code=>"PR"},
 {:name=>"Qatar", :code=>"QA"},
 {:name=>"Reunion", :code=>"RE"},
 {:name=>"Romania", :code=>"RO"},
 {:name=>"Russian Federation", :code=>"RU"},
 {:name=>"Rwanda", :code=>"RW"},
 {:name=>"Saint Barthelemy", :code=>"BL"},
 {:name=>"Saint Helena", :code=>"SH"},
 {:name=>"Saint Kitts And Nevis", :code=>"KN"},
 {:name=>"Saint Lucia", :code=>"LC"},
 {:name=>"Saint Martin", :code=>"MF"},
 {:name=>"Saint Pierre And Miquelon", :code=>"PM"},
 {:name=>"Saint Vincent And Grenadines", :code=>"VC"},
 {:name=>"Samoa", :code=>"WS"},
 {:name=>"San Marino", :code=>"SM"},
 {:name=>"Sao Tome And Principe", :code=>"ST"},
 {:name=>"Saudi Arabia", :code=>"SA"},
 {:name=>"Senegal", :code=>"SN"},
 {:name=>"Serbia", :code=>"RS"},
 {:name=>"Seychelles", :code=>"SC"},
 {:name=>"Sierra Leone", :code=>"SL"},
 {:name=>"Singapore", :code=>"SG"},
 {:name=>"Slovakia", :code=>"SK"},
 {:name=>"Slovenia", :code=>"SI"},
 {:name=>"Solomon Islands", :code=>"SB"},
 {:name=>"Somalia", :code=>"SO"},
 {:name=>"South Africa", :code=>"ZA"},
 {:name=>"South Georgia And Sandwich Isl.", :code=>"GS"},
 {:name=>"Spain", :code=>"ES"},
 {:name=>"Sri Lanka", :code=>"LK"},
 {:name=>"Sudan", :code=>"SD"},
 {:name=>"Suriname", :code=>"SR"},
 {:name=>"Svalbard And Jan Mayen", :code=>"SJ"},
 {:name=>"Swaziland", :code=>"SZ"},
 {:name=>"Sweden", :code=>"SE"},
 {:name=>"Switzerland", :code=>"CH"},
 {:name=>"Syrian Arab Republic", :code=>"SY"},
 {:name=>"Taiwan", :code=>"TW"},
 {:name=>"Tajikistan", :code=>"TJ"},
 {:name=>"Tanzania", :code=>"TZ"},
 {:name=>"Thailand", :code=>"TH"},
 {:name=>"Timor-Leste", :code=>"TL"},
 {:name=>"Togo", :code=>"TG"},
 {:name=>"Tokelau", :code=>"TK"},
 {:name=>"Tonga", :code=>"TO"},
 {:name=>"Trinidad And Tobago", :code=>"TT"},
 {:name=>"Tunisia", :code=>"TN"},
 {:name=>"Turkey", :code=>"TR"},
 {:name=>"Turkmenistan", :code=>"TM"},
 {:name=>"Turks And Caicos Islands", :code=>"TC"},
 {:name=>"Tuvalu", :code=>"TV"},
 {:name=>"Uganda", :code=>"UG"},
 {:name=>"Ukraine", :code=>"UA"},
 {:name=>"United Arab Emirates", :code=>"AE"},
 {:name=>"United Kingdom", :code=>"GB"},
 {:name=>"United States", :code=>"US"},
 {:name=>"United States Outlying Islands", :code=>"UM"},
 {:name=>"Uruguay", :code=>"UY"},
 {:name=>"Uzbekistan", :code=>"UZ"},
 {:name=>"Vanuatu", :code=>"VU"},
 {:name=>"Venezuela", :code=>"VE"},
 {:name=>"Viet Nam", :code=>"VN"},
 {:name=>"Virgin Islands, British", :code=>"VG"},
 {:name=>"Virgin Islands, U.S.", :code=>"VI"},
 {:name=>"Wallis And Futuna", :code=>"WF"},
 {:name=>"Western Sahara", :code=>"EH"},
 {:name=>"Yemen", :code=>"YE"},
 {:name=>"Zambia", :code=>"ZM"},
 {:name=>"Zimbabwe", :code=>"ZW"}]

with "countries" gem i only had to do this

ISO3166::Country.all.sort.map{|c| {value: c.alpha2 ,label: c.name}}