5.2. The Assignment Operator
identifier = expression
x = 4; // Assign 4 to the variable x x = y; // Assign the value of y to the variable x name = "dj duong"; // Assign a string to the variable name products = "Flash"; // Assign a string to the 4th element of products // Assign a number to the area property of square square.area = square.width * 2;
We may also perform multiple assignment operations at once, like this:
x = y = 4; // Set both x and y 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.
5.2.1. 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 of counter xPosition = xPosition + xVelocity; // Add xVelocity to xPosition score = score / 2; // Divide score 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 addition with assignment we use +=. To combine division with assignment, we use /=. The previous examples, hence, can be written more succinctly with compound assignment operators as follows:
counter += 10; xPosition += xVelocity; score /= 2;
Refer to Table 5-1 for a list of the compound assignment operators.
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