How do I use preg_match to test for spaces?

Also see this StackOverflow question that addresses this.

And, depending on if you want to detect tabs and other types of white space, you may want to look at the perl regular expression syntax for things such as \b \w and [:SPACE:]

If you're interested in any white space (including tabs etc), use \s

if (preg_match("/\\s/", $myString)) {
   // there are spaces
}

if you're just interested in spaces then you don't even need a regex:

if (strpos($myString, " ") !== false)