note 54544 deleted from function.preg-match by colder

Note Submitter: masterkumon at yahoo dot com ---- LITTLE NOTE ON PATTERN FOR NOOBIE : int preg_match ( string pattern, string subject) "/^[a-z0-9 ]*$/" / =begin/end pattern ^=matching from exactly beginning of subject $=matching from exactly end of subject []=match with any character in the "[]" brackets. [a-z0-9 ]=match with any character between a to z OR 0 to 9 OR "space" (there is space between 9 and ]) *=the number of matching character in the subject can be 0 or more. Actually "[]"brackets only match for 1 character position so if you to match 1 or more use "+" match 0 or more use "*" match 5 characters use {5} match 5 to 6 characters use {5,6} on the "*" position in the example. <? preg_match ($pattern, $subject); ?> $pattern="/^[a-z0-9 ]*$/"; $subject="abcdefgadfafda65" ->TRUE $subject="abcdefg ad f afda 65" ->TRUE $pattern="/[a-z0-9 ]*/"; $subject="$$abcdefgadfafda65><" ->TRUE why? because there's no "^" on the beginning and no "$" on the end of $pattern. So the regex matchs entire $subject and found the correct one on the middle, it is OK because there's no "^" and "$" boundary. If you put only one either "^" nor "$" the regex will matchs for head nor tail of $subject only. LITTLE MORE ADVANCE checking file name string that must contain 3 characters extension ".xxx" and the file name contains alphabetic character only. here is the pattern "/^[a-zA-Z0-9]*\.[a-zA-Z0-9]{3}$/" \.=there is "." character for extension separation. Constant character must be preceeded by an "\". {3}= 3 characters extension OTHER SPECIAL CHARACTERS. I haven't examined them. .=wild card for any character |=OR