not
, and
, and or
Conditions can be combined logically:
not
cond
cond1 and
cond2 and
cond3 and ...
cond1 or
cond2 or
cond3 or ...
The operator not
takes exactly one argument. If its argument contains
another logical operator, put it in parentheses ()
, as in
not (
cond1 or
cond2)
.
The operators and
and or
may not be mixed as in
cond1
and
cond2 or
cond3; here the order of
evaluation would be ambiguous. Use parentheses
()
to indicate in wich
order the condition is to be evaluated, as in
(
cond1 and
cond2) or
cond3.