array_map -- Applies the callback to the elements of the given arrays array_map() returns an array containing all the elements of arr1 after applying the callback function to each one. The number of parameters that the callback function accepts should match the number of arrays passed to the array_map()

ereg_replace -- Replace regular expression This function scans string for matches to pattern, then replaces the matched text with replacement. The modified string is returned. (Which may mean that the original string is returned if there are no matches to be replaced.) If pattern contains parenthesized substrings, replacement may contain substrings of the form \\digit, which will be replaced by the text matching the digit'th parenthesized substring; \\0 will produce the entire contents of string. Up to nine substrings may be used. Parentheses may be nested, in which case they are counted by the opening parenthesis. If no matches are found in string, then string will be returned unchanged.

in_array -- Checks if a value exists in an array Searches haystack for needle and returns TRUE if it is found in the array, FALSE otherwise. If the third parameter strict is set to TRUE then the in_array() function will also check the types of the needle in the haystack.

preg_match_all -- Perform a global regular expression match Searches subject for all matches to the regular expression given in pattern and puts them in matches in the order specified by flags. After the first match is found, the subsequent searches are continued on from end of the last match.

mixed preg_replace ( mixed pattern, mixed replacement, mixed subject [, int limit [, int &count]] ) Searches subject for matches to pattern and replaces them with replacement.

str_replace -- Replace all occurrences of the search string with the replacement string