|
Used to perform logical negation on an expression.
result = !expression
result
Any variable.
expression
Any expression.
The following table illustrates how result is determined.
If expression is |
Then result is |
True |
False |
False |
True |
All unary operators, such as the ! operator, evaluate expressions as follows:
· If applied to undefined or null expressions, a run-time error is raised.
· Objects are converted to strings.
· Strings are converted to numbers if possible. If not, a run-time error is raised.
· Boolean values are treated as numbers (0 if false, 1 if true).
The operator is applied to the resulting number.
For the ! operator, if expression is nonzero, result is zero. If expression is zero, result is 1.
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Legal Notice.