MACROMEDIA FLASH MX, Reference

Page: 729 / 1104

set variable 729
set variable
Availability
Flash Player 4.
Usage
set(" variableString ", expression )
Parameters
variableString
A string that names a variable to hold the value of the
expression
parameter.
expression
A value assigned to the variable.
Returns
Nothing.
Description
Statement; assigns a value to a variable. A variable is a container that holds data. The container is
always the same, but the contents can change. By changing the value of a variable as the SWF file
plays, you can record and save information about what the user has done, record values that
change as the SWF file plays, or evaluate whether a condition is
true
or
false
.
Variables can hold any data type (for example, String, Number, Boolean, Object, or MovieClip).
The Timeline of each SWF file and movie clip has its own set of variables, and each variable has
its own value independent of variables on other Timelines.
Strict data typing is not supported inside a
set
statement. If you use this statement to set a
variable to a value whose data type is different from the data type associated with the variable in a
class file, no compiler error is generated.
A subtle but important distinction to bear in mind is that the parameter
variableString
is a
string, not a variable name. If you pass an existing variable name as the first parameter to
set()
without enclosing the name in quotation marks (
"")
, the variable is evaluated before the value of
expression
is assigned to it. For example, if you create a string variable named
myVariable
and
assign it the value “Tuesday,” and then forget to use quotation marks, you will inadvertently create
a new variable named
Tuesday
that contains the value you intended to assign to
myVariable
:
var myVariable:String = "Tuesday";
set (myVariable, "Saturday");
trace(myVariable); // outputs Tuesday
trace(Tuesday); // outputs Saturday
You can avoid this situation by using quotation marks (""):
set ("myVariable", "Saturday");
trace(myVariable); //outputs Saturday
Example
In the following example, you assign a value to a variable. You are assigning the value of
"Jakob"
to the
name
variable.
CHAPTER 2
ActionScript Language Reference