Parts of a molecule may also be distinguished using equality, inequality and ordering operators on their properties. The format of such comparison expression is a property name, followed by a comparison operator and then an integer value.
The atom properties that may be used in RasMol are atomno for the atom serial number, elemno for the atom's atomic number (element), resno for the residue number, radius for the spacefill radius in RasMol units (or zero if not represented as a sphere) and temperature for the PDB anisotropic temperature value.
The equality operator is denoted either "=" or "==". The inequality operator as either "<>", "!=" or "/=". The ordering operators are "<" for less than, "<=" for less than or equal to, ">" for greater than, and ">=" for greater than or equal to.
Examples: resno < 23 temperature >= 900 atomno == 487