Translating characters and substrings
The strtr( ) function translates characters or substrings in a subject string:
string strtr(string subject, string from, string to) string strtr(string subject, array map)
When called with three arguments, strtr( ) translates the characters in the subject string that match those in the from string with the corresponding characters in the to string. When called with two arguments, a subject string and an array map, occurrences of the map keys in subject are replaced with the corresponding map values.
The following example uses strtr( ) to replace all lowercase vowels with the corresponding umlauted character:
$mischief = strtr("command.com", "aeiou", "äëïöü");
print $mischief; // prints cömmänd.cöm
When an associative array is passed as a translation map, strtr( ) replaces substrings rather than characters. The following example shows how strtr( ) can expand acronyms:
// Short list of acronyms used in e-mail
$glossary = array("BTW"=>"by the way",
"IMHO"=>"in my humble opinion",
"IOW"=>"in other words",
"OTOH"=>"on the other hand");
// Maybe now I can understand
print strtr($geekMail, $glossary);