Good way to create a function

I'm trying to create a function that replace code of countries by their name or inverse. Here is my code:

function _parseCountry($country,$from,$to){

$name = array("AFGHANISTAN","ALBANIA","ALGERIA","AMERICAN SAMOA","ANDORRA","ANGOLA","ANGUILLA","ANTARCTICA","ANTIGUA AND BARBUDA","ARGENTINA","ARMENIA","ARUBA","AUSTRALIA","AUSTRIA","AZERBAIJAN","BAHAMAS","BAHRAIN","BANGLADESH","BARBADOS","BELARUS","BELGIUM","BELIZE","BENIN","BERMUDA","BHUTAN","BOLIVIA","BOSNIA AND HERZEGOVINA","BOTSWANA","BOUVET ISLAND","BRAZIL","BRITISH INDIAN OCEAN TERRITORY","BRUNEI","BULGARIA","BURKINA FASO","BURMA","BURUNDI","CAMBODIA","CAMEROON","CANADA","CANTON AND ENDERBURY ISLANDS","CAPE VERDE","CAYMAN ISLANDS","CENTRAL AFRICAN REPUBLIC","CHAD","CHILE",开发者_JS百科"CHINA","CHRISTMAS ISLAND","COCOS (KEELING) ISLANDS","COLOMBIA","COMOROS","CONGO","COOK ISLANDS","COSTA RICA","COTE D'IVOIRE","CROATIA","CUBA","CYPRUS","CZECH REPUBLIC","DEMOCRATIC YEMEN","DENMARK","DJIBOUTI","DOMINICA","DOMINICAN REPUBLIC","DRONNING MAUD LAND","EAST TIMOR","ECUADOR","EGYPT","EL SALVADOR","EQUATORIAL GUINEA","ERITREA","ESTONIA","ETHIOPIA","FALKLAND ISLANDS","FAROE ISLANDS","FIJI","FINLAND","FRANCE","FRANCE METROPOLITAN","FRENCH GUIANA","FRENCH POLYNESIA","FRENCH SOUTHERN TERRITORIES","GABON","GAMBIA","GEORGIA","GERMANY","GHANA","GIBRALTAR","GREECE","GREENLAND","GRENADA","GUADELOUPE","GUAM","GUATEMALA","GUINEA","GUINEA-BISSAU","GUYANA","HAITI","HEARD AND MC DONALD ISLANDS","HONDURAS","HONG KONG","HUNGARY","ICELAND","INDIA","INDONESIA","IRAN","IRAQ","IRELAND","ISRAEL","ITALY","JAMAICA","JAPAN","JOHNSTON ISLAND","JORDAN","KAZAKHSTAN","KENYA","KIRIBATI","KOSOVO","KUWAIT","KYRGYZSTAN","LAOS","LATVIA","LEBANON","LESOTHO","LIBERIA","LIBYA","LIECHTENSTEIN","LITHUANIA","LUXEMBOURG","MACAU","MACEDONIA","MADAGASCAR","MALAWI","MALAYSIA","MALDIVES","MALI","MALTA","MARSHALL ISLANDS","MARTINIQUE","MAURITANIA","MAURITIUS","MAYOTTE","MEXICO","MICRONESIA - FEDERATED STATES OF","MIDWAY ISLANDS","MOLDOVA","MONACO","MONGOLIA","MONTSERRAT","MOROCCO","MOZAMBIQUE","MYANMAR","NAMIBIA","NAURU","NEPAL","NETHERLANDS","NETHERLANDS ANTILLES","NEUTRAL ZONE","NEW CALEDONIA","NEW ZEALAND","NICARAGUA","NIGER","NIGERIA","NIUE","NORFOLK ISLAND","NORTH KOREA","NORTHERN MARIANA ISLANDS","NORWAY","OMAN","PAKISTAN","PALAU","PALESTINIAN TERRITORIES","PANAMA","PAPUA NEW GUINEA","PARAGUAY","PERU","PHILIPPINES","PITCAIRN ISLANDS","POLAND","PORTUGAL","PUERTO RICO","QATAR","REUNION","ROMANIA","RUSSIA","RWANDA","SAINT KITTS AND NEVIS","SAINT LUCIA","SAINT VINCENT AND THE GRENADINES","SAMOA","SAN MARINO","SAO TOME AND PRINCIPE","SAUDI ARABIA","SENEGAL","SERBIA","SERBIA AND MONTENEGRO","SEYCHELLES","SIERRA LEONE","SINGAPORE","SLOVAKIA","SLOVENIA","SOLOMON ISLANDS","SOMALIA","SOUTH AFRICA","SOUTH GEORGIA AND THE SOUTH SANDWICH ISLANDS","SOUTH KOREA","SPAIN","SRI LANKA","ST. HELENA","ST. PIERRE AND MIQUELON","SUDAN","SURINAME","SVALBARD AND JAN MAYEN ISLANDS","SWAZILAND","SWEDEN","SWITZERLAND","SYRIA","TAIWAN","TAJIKISTAN","TANZANIA","THAILAND","TIMOR-LESTE","TOGO","TOKELAU","TONGA","TRINIDAD AND TOBAGO","TUNISIA","TURKEY","TURKMENISTAN","TURKS AND CAICOS ISLANDS","TUVALU","UGANDA","UKRAINE","UNITED ARAB EMIRATES","UNITED KINGDOM","UNITED STATES","UNITED STATES MINOR OUTLYING ISLANDS","URUGUAY","UZBEKISTAN","VANUATU","VATICAN CITY STATE (HOLY SEE)","VENEZUELA","VIETNAM","VIRGIN ISLANDS (BRITISH)","VIRGIN ISLANDS (U.S.)","WAKE ISLAND","WALLIS AND FUTUNA ISLANDS","WESTERN SAHARA","YEMEN","ZAIRE","ZAMBIA","ZIMBABWE");

$iso = array("AF","AL","DZ","AS","AD","AO","AI","AQ","AG","AR","AM","AW","AU","AT","AZ","BS","BH","BD","BB","BY","BE","BZ","BJ","BM","BT","BO","BA","BW","BV","BR","IO","BN","BG","BF","BU","BI","KH","CM","CA","CT","CV","KY","CF","TD","CL","CN","CX","CC","CO","KM","CG","CK","CR","CI","HR","CU","CY","CZ","YD","DK","DJ","DM","DO","NQ","TP","EC","EG","SV","GQ","ER","EE","ET","FK","FO","FJ","FI","FR","FX","GF","PF","TF","GA","GM","GE","DE","GH","GI","GR","GL","GD","GP","GU","GT","GN","GW","GY","HT","HM","HN","HK","HU","IS","IN","ID","IR","IQ","IE","IL","IT","JM","JP","JT","JO","KZ","KE","KI","KV","KW","KG","LA","LV","LB","LS","LR","LY","LI","LT","LU","MO","MK","MG","MW","MY","MV","ML","MT","MH","MQ","MR","MU","YT","MX","FM","MI","MD","MC","MN","MS","MA","MZ","MM","NA","NR","NP","NL","AN","NT","NC","NZ","NI","NE","NG","NU","NF","KP","MP","NO","OM","PK","PW","PS","PA","PG","PY","PE","PH","PN","PL","PT","PR","QA","RE","RO","RU","RW","KN","LC","VC","WS","SM","ST","SA","SN","RS","CS","SC","SL","SG","SK","SI","SB","SO","ZA","GS","KR","ES","LK","SH","PM","SD","SR","SJ","SZ","SE","CH","SY","TW","TJ","TZ","TH","TL","TG","TK","TO","TT","TN","TR","â„¢","TC","TV","UG","UA","AE","GB","US","UM","UY","UZ","VU","VA","VE","VN","VG","VI","WK","WF","EH","YE","ZR","ZM","ZW");

$iso3 = array("AFG","ALB","DZA","ASM","AND","AGO","AIA","ATA","ATG","ARG","ARM","ABW","AUS","AUT","AZE","BHS","BHR","BGD","BRB","BLR","BEL","BLZ","BEN","BMU","BTN","BOL","BIH","BWA","BVT","BRA","IOT","BRN","BGR","BFA","BUR","BDI","KHM","CMR","CAN","CTE","CPV","CYM","CAF","TCD","CHL","CHN","CXR","CCK","COL","COM","COG","COK","CRI","CIV","HRV","CUB","CYP","CZE","YMD","DNK","DJI","DMA","DOM","DML","TMP","ECU","EGY","SLV","GNQ","ERI","EST","ETH","FLK","FRO","FJI","FIN","FRA","FXX","GUF","PYF","ATF","GAB","GMB","GEO","DEU","GHA","GIB","GRC","GRL","GRD","GLP","GUM","GTM","GIN","GNB","GUY","HTI","HMD","HND","HKG","HUN","ISL","IND","IDN","IRN","IRQ","IRL","ISR","ITA","JAM","JPN","JTN","JOR","KAZ","KEN","KIR","KVV","KWT","KGZ","LAO","LVA","LBN","LSO","LBR","LBY","LIE","LTU","LUX","MAC","MKD","MDG","MWI","MYS","MDV","MLI","MLT","MHL","MTQ","MRT","MUS","MYT","MEX","FSM","MID","MDA","MCO","MNG","MSR","MAR","MOZ","MMR","NAM","NRU","NPL","NLD","ANT","NTZ","NCL","NZL","NIC","NER","NGA","NIU","NFK","PRK","MNP","NOR","OMN","PAK","PLW","PSE","PAN","PNG","PRY","PER","PHL","PCN","POL","PRT","PRI","QAT","REU","ROM","RUS","RWA","KNA","LCA","VCT","WSM","SMR","STP","SAU","SEN","SRB","SCG","SYC","SLE","SGP","SVK","SVN","SLB","SOM","ZAF","SGS","KOR","ESP","LKA","SHN","SPM","SDN","SUR","SJM","SWZ","SWE","CHE","SYR","TWN","TJK","TZA","THA","TLS","TGO","TKL","TON","TTO","TUN","TUR","TKM","TCA","TUV","UGA","UKR","ARE","GBR","USA","UMI","URY","UZB","VUT","VAT","VEN","VNM","VGB","VIR","WAK","WLF","ESH","YEM","ZAR","ZMB","ZWE");

switch ($from){
case 'name':
$from = $name; 
break;
case 'iso':
$from = $iso; 
break;
case 'iso3':
$from = $iso3; 
break; 
}

switch ($to){
case 'name':
$to = $name; 
break;
case 'iso':
$to = $iso; 
break;
case 'iso3':
$to = $iso3; 
break; 
}

$country = str_replace($country, $from, $to);

return $country ;

}

I have the feeling that I'm doing something wrong, isn't it?

You could use variable variables to remove the switch statements; so your function would just become:

$country = str_replace($country, $$from, $$to);

However this could introduce some security risks, you should check to see if $from and $to are valid country codes.

Also if possible, you could put the information in your database. That way you can easily add new countries and such, and you have less hardcoded data.