MACROMEDIA FLEX, Reference

Page: 96 / 830

96 Chapter 5: ActionScript Core Language Elements
Parameters
None.
Returns
The value of
expression1
,
expression2
, and so on.
Description
Operator; evaluates
expression1
, then
expression2
, and so on. This operator is primarily used
with the
for
loop statement and is often used with the parentheses () operator.
For more information, see “Operator precedence and associativity” on page 32 .
Example
The following example uses the comma (,) operator in a
for
loop:
for (i = 0, j = 0; i < 3 && j < 3; i++, j+=2) {
trace("i = " + i + ", j = " + j);
}
// Output:
// i = 0, j = 0
// i = 1, j = 2
The following example uses the comma (,) operator without the parentheses () operator and
illustrates that the comma operator returns only the value of the first expression without the
parentheses () operator:
var v:Number = 0;
v = 4, 5, 6;
trace(v); // output: 4
The following example uses the comma (,) operator with the parentheses () operator and
illustrates that the comma operator returns the value of the last expression when used with the
parentheses () operator:
var v:Number = 0;
v = (4, 5, 6);
trace(v); // output: 6
The following example uses the comma (,) operator without the parentheses () operator and
illustrates that the comma operator sequentially evaluates all of the expressions but returns the
value of the first expression. The second expression,
z++
, is evaluated and
z
is incremented by
one.
var v:Number = 0;
var z:Number = 0;
v = v + 4 , z++, v + 6;
trace(v); // output: 4
trace(z); // output: 1
The following example is identical to the previous example except for the addition of the
parentheses () operator and illustrates once again that, when used with the parentheses () operator,
the comma (,) operator returns the value of the last expression in the series:
var v:Number = 0;