php正则表达式不允许字符串中的DOT

Question

Here is my code at the moment, allowing ONLY a-z and 0-9. If I wanted a similar regExp that will NOT allow any string containing a dot (.) how would I have to modify it?

if ( preg_match('/^[a-z0-9_]+$/',$myExtraField) == false ) {

This is inside a symfony2 form class, not sure whether the regExp is the same as flat PHP hence I included my present regExp... never had the time to dive into regExp and hardly ever use it.

Answer 1

The simplest check you could do would be

strpos($myExtraField, ".") === false

If you really wanted to use a regex, you could invert preg_match("/\./") or just do a check like preg_match("/^[^.]*$/")