The Assignment Operator
We’ve already used the assignment operator frequently. It can place a value into a variable, array element, or object property. Assignment operations take the form:
identifier
=expression
The
identifier
is the variable, array element, or
object property into which we want to place our value. The
expression
represents the value (i.e.,
data) that we want to store. For example:
x = 4; // Assign 4 to the variablex
x = y; // Assign the value ofy
to the variablex
name = "dj duong"; // Assign a string to the variablename
products[3] = "Flash"; // Assign a string to the 4th element ofproducts
// Assign a number to the area property ofsquare
square.area = square.width * 2;
We may also perform multiple assignment operations at once, like this:
x = y = 4; // Set bothx
andy
to 4
Remember that assignment operations have right-to-left associativity,
so 4 is assigned first to y
then the value of
y
(which is now 4) is assigned to
x
.
Combining Operations with Assignment
Assignment operations are often used to set a variable’s new value based in part on its old value. For example:
counter = counter + 10; // Add 10 to the current value ofcounter
xPosition = xPosition + xVelocity; // AddxVelocity
toxPosition
score = score / 2; // Dividescore
by two
ActionScript supports a shorthand version of assignment, called compound assignment that combines operators such as +, -, / with the assignment operator to form a single “calculate-while-assigning” operation. So, to combine ...
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