ereg — Regular expression match

ereg — Regular expression match
Searches a string for matches to the regular expression given in pattern in a case-sensitive way.

int ereg ( string $pattern , string $string [, array &$regs ] )
pattern - Case sensitive regular expression.
string- The input string.

regs -If matches are found for parenthesized substrings of pattern and the function is called with the third argument regs , the matches will be stored in the elements of the array regs .$regs[1] will contain the substring which starts at the first left parenthesis; $regs[2] will contain the substring starting at the second, and so on. $regs[0] will contain a copy of the complete string matched.

Return Values

Returns the length of the matched string if a match for pattern was found in string , or FALSE if no matches were found or an error occurred.
If the optional parameter regs was not passed or the length of the matched string is 0, this function returns 1.

Example#1
The following code snippet takes a date in ISO format (YYYY-MM-DD) and prints it in DD.MM.YYYY format:

if (ereg ("([0-9]{4})-([0-9]{1,2})-([0-9]{1,2})", $date, $regs)) {
echo "$regs[3].$regs[2].$regs[1]";
} else {
echo "Invalid date format: $date";
}
?>
Example#2
Check if string only contains letters and numbers.
if (ereg("[^A-Za-z0-9]", $string)) {
echo "Error: String can only contain letters and numbers!";
exit();
}
Example#3
This is intended to validate fully specified (international) phone numbers without forcing the user to use the full international format and giving them maximum reasonable flexibility including an optional extension number.
Allows numbers plus any of: space():.ext,+-
Example: +44(0)113 249-0442 ext:1234
The code matches any combination of the allowed character set.
php
$phoneNumber="+44(0)113 249-0442 ext:1234";
$regex="[0-9 ():.ext,+-]{".strlen($phoneNumber)."}";

if(ereg($regex,$phoneNumber)){
echo "ok";
}else {
echo "invalid phone number";
}
?>