Học biểu thức chính qui trong php
My Code: Pattern Usage >foo The string "foo" ^foo "foo" at the start of a string foo$ "foo" at the end of a string ^foo$ "foo" when it is alone on a string [abc] a, b, or c [a-z] Any lowercase letter [^A-Z] Any character that is not a uppercase letter (gif|jpg) Matches either "gif" or "jpeg" [a-z]+ One or more lowercase letters [0-9\.\- ] Аny number, dot, or minus sign ^[a-zA-Z0-9_]{1,}$ Any word of at least one letter, number or _ ([wx])([yz]) wy, wz, xy, or xz [^A-Za-z0-9] Any symbol (not a number or a letter) ([A-Z]{3}|[0-9]{4}) Matches three letters or four numbers Special Sequences \w - Any “word” character (a-z 0-9 _) \W - Any non “word” character \s - Whitespace (space, tab CRLF) ...