... PHP 4 >= 4.0.0) array_flip -- Flip all the values of an array . array array_flip ( array trans) . array_flip() returns an array in flip order, i.e. keys from trans become values and trans 's values become keys. ... If a value has several occurrences, the latest key will be used as its values, and all others will be lost. array_flip() returns FALSE if it fails. Example 1. array_flip() example . trans = array_flip ($trans); $original = strtr ($str, $trans); . ... now $trans is : . ...