Operator Effect
= equals (exact value of a property, consider ThemeKey Debug to get an impression of the possible values)
! not equals
* contains
!* not contains
< less than (alphanumeric values are treated in alphabetical order: "A" is less than "B" but "B" is less than "a")
<= less than or equal to (alphanumeric values are treated in alphabetical order: "a" is less than "b" but "B" is less than "a" and "A" is less than "a")
> greater (alphanumeric values are treated in alphabetical order: "b" is greater than "a" but "a" is greater than "B")
=> greater than or equal (alphanumeric values are treated in alphabetical order: "b" is greater than "a" but "a" is greater than "B" and "a" is greater than "A")
~ regular expression, including delimiters and modifiers (see PHP Manual)
!~ non matching regular expression, including delimiters and modifiers (see PHP Manual)