User Guide

68 ActionScript Language and Syntax

In ActionScript 3.0, the Number() function no longer supports octal, or base 8, numbers. If

you supply a string with a leading zero to the ActionScript 2.0

Number() function, the

number is interpreted as an octal number, and converted to its decimal equivalent. This is not

true with the

Number() function in ActionScript 3.0, which instead ignores the leading zero.

For example, the following code generates different output when compiled using different

versions of ActionScript:

trace(Number("044"));

// ActionScript 3.0 44

// ActionScript 2.0 36

Casting is not necessary when a value of one numeric type is assigned to a variable of a

different numeric type. Even in strict mode, the numeric types are implicitly converted to the

other numeric types. This means that in some cases, unexpected values may result when the

range of a type is exceeded. The following examples all compile in strict mode, though some

will generate unexpected values:

var sampleUINT:uint = -3; // Assign value of type int and Number.

trace(sampleUINT); // 4294967293

var sampleNum:Number = sampleUINT; // Assign value of type int and uint.

trace(sampleNum) // 4294967293

var sampleINT:int = uint.MAX_VALUE + 1; // Assign value of type Number.

trace(sampleINT); // 0

sampleINT = int.MAX_VALUE + 1; // Assign value of type uint and Number.

trace(sampleINT); // -2147483648

The following table summarizes the results of casting to the Number, int, or uint data type

from other data types.

Data type or value Result of conversion to Number, int or uint

Boolean If the value is true, 1; otherwise, 0.

Date The internal representation of the Date object, which is the number

of milliseconds since midnight January 1, 1970, universal time.

null

Object If the instance is

null and converted to Number, NaN; otherwise, 0.

String A number if Flash Player can convert the string to a number;

otherwise,

NaN if converted to Number or 0 if converted to int or uint.

undefined

If converted to Number, NaN; if converted to int or uint, 0.