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A special value representing negative Infinity. The value of this constant is the same as Number.NEGATIVE_INFINITY.

Related API Elements

trace(0 / 0);  // NaN
trace(7 / 0);  // Infinity
trace(-7 / 0); // -Infinity

A special value representing positive Infinity. The value of this constant is the same as Number.POSITIVE_INFINITY.

Related API Elements

trace(0 / 0);  // NaN
trace(7 / 0);  // Infinity
trace(-7 / 0); // -Infinity

A special member of the Number data type that represents a value that is "not a number" (NaN). When a mathematical expression results in a value that cannot be expressed as a number, the result is NaN. The following list describes common expressions that result in NaN.

• Division by 0 results in NaN only if the divisor is also 0. If the divisor is greater than 0, division by 0 results in Infinity. If the divisor is less than 0, division by 0 results in -Infinity;
• Square root of a negative number;
• The arcsine of a number outside the valid range of 0 to 1;
• Infinity subtracted from Infinity;
• Infinity or -Infinity divided by Infinity or -Infinity;
• Infinity or -Infinity multiplied by 0;

The NaN value is not a member of the int or uint data types.

The NaN value is not considered equal to any other value, including NaN, which makes it impossible to use the equality operator to test whether an expression is NaN. To determine whether a number is the NaN function, use isNaN().

Related API Elements

A special value that applies to untyped variables that have not been initialized or dynamic object properties that are not initialized. In ActionScript 3.0, only variables that are untyped can hold the value undefined, which is not true in ActionScript 1.0 and ActionScript 2.0. For example, both of the following variables are undefined because they are untyped and unitialized:

• var foo;
• var bar:*;

The undefined value also applies to uninitialized or undefined properties of dynamic objects. For example, if an object is an instance of the Object class, the value of any dynamically added property is undefined until a value is assigned to that property.

Results vary when undefined is used with various functions:

• The value returned by String(undefined) is "undefined" (undefined is converted to a string).
• The value returned by Number(undefined) is NaN.
• The value returned by int(undefined) and uint(undefined) is 0.
• The value returned by Object(undefined) is a new Object instance.
• When the value undefined is assigned to a typed variable, the value is converted to the default value of the data type.

Do not confuse undefined with null. When null and undefined are compared with the equality (==) operator, they compare as equal. However, when null and undefined are compared with the strict equality (===) operator, they compare as not equal.

Related API Elements

// trace value of untyped and uninitialized variable
var myVar;
trace(myVar); // undefined

dynamic class A {}
var obj:A = new A()

// trace undefined property of obj
trace(obj.propName); // undefined

Creates a new array. The array can be of length zero or more, or an array populated by a single specified object.

• Calling Array() with no arguments returns an empty array.
• Calling Array() with a single integer argument returns an array of the specified length, but whose elements have undefined values.
• Calling Array() with a specified object returns an array with one element of the specified object.

Note: If you try to use the Array() function to create a new array, and pass several values as parameters to populate the array, you'll get a compiler error. The the Array() function only allows one parameter. Use the Array class constructor, instead, to create and populate an array of several values.

The Array() function does not cast the type of an object to an array. Use the as operator for explicit type conversion, or type casting, when the argument is not a primitive value. For more information, see the Example section of this entry. If you pass an object as a parameter to the Array() function, a new array is created containing the object as an element.

Parameters

Related API Elements

var obj:Object = [ "a", "b", "c" ];
      
var newArray:Array = Array( obj );

trace(newArray == obj);    // false
trace(newArray[0] == obj); // true
trace(newArray[0][0])      // a
trace(newArray[0][1])      // b
trace(newArray[0][2])      // c

var obj:Object = [ "a", "b", "c" ];
      
var newArray:Array = obj as Array;

trace(newArray == obj); // true
trace(newArray[0]);     // a
trace(newArray[1]);     // b
trace(newArray[2]);     // c

Converts the expression parameter to a Boolean value and returns the value.

The return value depends on the data type and value of the argument, as described in the following table:

Unlike previous versions of ActionScript, the Boolean() function returns the same results as does the Boolean class constructor.

Parameters

Decodes an encoded URI into a string. Returns a string in which all characters previously encoded by the encodeURI function are restored to their unencoded representation.

The following table shows the set of escape sequences that are not decoded to characters by the decodeURI function. Use decodeURIComponent() to decode the escape sequences in this table.

Parameters

Related API Elements

package {
    import flash.display.Sprite;

    public class DecodeURIExample extends Sprite {
        public function DecodeURIExample() {
            var uri:String = "http://www.example.com/application.jsp?user=<user name='some user'></user>";
            var encoded:String = encodeURI(uri);
            var decoded:String = decodeURI(encoded);
            trace(uri);        // http://www.example.com/application.jsp?user=<user name='some user'></user>
            trace(encoded);    // http://www.example.com/application.jsp?user=%3Cuser%20name='some%20user'%3E%3C/user%3E
            trace(decoded);    // http://www.example.com/application.jsp?user=<user name='some user'></user>
        }
    }
}

Decodes an encoded URI component into a string. Returns a string in which all characters previously escaped by the encodeURIComponent function are restored to their uncoded representation.

This function differs from the decodeURI() function in that it is intended for use only with a part of a URI string, called a URI component. A URI component is any text that appears between special characters called component separators (: / ; and ? ). Common examples of a URI component are "http" and "www.adobe.com".

Another important difference between this function and decodeURI() is that because this function assumes that it is processing a URI component it treats the escape sequences that represent special separator characters (; / ? : @ & = + $ , #) as regular text that should be decoded.

Parameters

Related API Elements

Encodes a string into a valid URI (Uniform Resource Identifier). Converts a complete URI into a string in which all characters are encoded as UTF-8 escape sequences unless a character belongs to a small group of basic characters.

The following table shows the entire set of basic characters that are not converted to UTF-8 escape sequences by the encodeURI function.

Parameters

Related API Elements

package {
    import flash.display.Sprite;

    public class EncodeURIExample extends Sprite {
        public function EncodeURIExample() {
            var uri:String = "http://www.example.com/application.jsp?user=<user name='some user'></user>";
            var encoded:String = encodeURI(uri);
            var decoded:String = decodeURI(encoded);
            trace(uri);        // http://www.example.com/application.jsp?user=<user name='some user'></user>
            trace(encoded);    // http://www.example.com/application.jsp?user=%3Cuser%20name='some%20user'%3E%3C/user%3E
            trace(decoded);    // http://www.example.com/application.jsp?user=<user name='some user'></user>
        }
    }
}

Encodes a string into a valid URI component. Converts a substring of a URI into a string in which all characters are encoded as UTF-8 escape sequences unless a character belongs to a very small group of basic characters.

The encodeURIComponent() function differs from the encodeURI() function in that it is intended for use only with a part of a URI string, called a URI component. A URI component is any text that appears between special characters called component separators (: / ; and ? ). Common examples of a URI component are "http" and "www.adobe.com".

Another important difference between this function and encodeURI() is that because this function assumes that it is processing a URI component it treats the special separator characters (; / ? : @ & = + $ , #) as regular text that should be encoded.

The following table shows all characters that are not converted to UTF-8 escape sequences by the encodeURIComponent function.

Parameters

Related API Elements

Converts the parameter to a string and encodes it in a URL-encoded format, where most nonalphanumeric characters are replaced with % hexadecimal sequences. When used in a URL-encoded string, the percentage symbol (%) is used to introduce escape characters, and is not equivalent to the modulo operator (%).

The following table shows all characters that are not converted to escape sequences by the escape() function.

Note: Use the encodeURIComponent() function, instead of the escape() function, to treat special separator characters (@ + /) as regular text to encode.

Parameters

Related API Elements

Converts a given numeric value to an integer value. Decimal values are truncated at the decimal point.

Parameters

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Returns true if the value is a finite number, or false if the value is Infinity or -Infinity. The presence of Infinity or -Infinity indicates a mathematical error condition such as division by 0.

Parameters

Returns true if the value is NaN(not a number). The isNaN() function is useful for checking whether a mathematical expression evaluates successfully to a number. The most common use of isNaN() is to check the value returned from the parseInt()and parseFloat() functions. The NaN value is a special member of the Number data type that represents a value that is "not a number."

Note: The NaN value is not a member of the int or uint data types.

The following table describes the return value of isNaN() on various input types and values. (If your compiler warnings are set to Strict Mode, some of the following operations will generate compiler warnings.)

Parameters

Determines whether the specified string is a valid name for an XML element or attribute.

Parameters

Converts a given value to a Number value. The following table shows the result of various input types:

Parameters

More examples

Every value in ActionScript 3.0 is an object, which means that calling Object() on a value returns that value.

Parameters

Converts a string to a floating-point number. The function reads, or parses, and returns the numbers in a string until it reaches a character that is not a part of the initial number. If the string does not begin with a number that can be parsed, parseFloat() returns NaN. White space preceding valid integers is ignored, as are trailing nonnumeric characters.

Parameters

Converts a string to an integer. If the specified string in the parameters cannot be converted to a number, the function returns NaN. Strings beginning with 0x are interpreted as hexadecimal numbers. Unlike in previous versions of ActionScript, integers beginning with 0 are not interpreted as octal numbers. You must specify a radix of 8 for octal numbers. White space and zeroes preceding valid integers are ignored, as are trailing nonnumeric characters.

Parameters

Returns a string representation of the specified parameter.

The following table shows the result of various input types:

Parameters

More examples

Displays expressions, or writes to log files, while debugging. A single trace statement can support multiple arguments. If any argument in a trace statement includes a data type other than a String, the trace function invokes the associated toString() method for that data type. For example, if the argument is a Boolean value the trace function invokes Boolean.toString() and displays the return value.

Parameters

package {
    import flash.display.Sprite;

    public class TraceExample extends Sprite {

        public function TraceExample() {
            trace("Hello World");
        }
    }
}

Converts a given numeric value to an unsigned integer value. Decimal values are truncated at the decimal point.

The following table describes the return value of uint() on various input types and values.

Parameters

Related API Elements

Evaluates the parameter str as a string, decodes the string from URL-encoded format (converting all hexadecimal sequences to ASCII characters), and returns the string.

Parameters

Creates a new Vector instance whose elements are instances of the specified data type. When calling this function, you specify the data type of the result Vector's elements (the Vector's base type) using a type parameter. This function uses the same syntax that's used when declaring a Vector instance or calling the new Vector.<T>() constructor:

var v:Vector.<String> = Vector.<String>(["Hello", "World"]);

The resulting Vector is populated with the values in the elements of the sourceArray argument. If the sourceArray argument is already a Vector.<T> instance where T is the base type, the function returns that Vector. Otherwise, the result Vector is populated with the elements of the sourceArray Array or Vector.

In either case, the data type of all the elements of the sourceArray argument must match the base type T specified in the function call.

If the sourceArray argument has length 0, the function returns an empty Vector.

If a Vector is passed as the sourceArray argument and its base type is not T, or if an Array is passed and its elements are not all instances of data type T, an attempt is made to convert the values to the base type. If the values can be automatically converted, the result Vector contains the converted values. If no conversion can be made, an error occurs.

Likewise, if an element in the sourceArray argument is an instance of a subclass of the base type T, the call succeeds and the element is added to the resulting Vector. This works even if the sourceArray argument is a Vector whose base type is a subclass of T. In fact, this is the only way to convert a Vector with base type T to a Vector with a base type that's a superclass of T.

For example, the following code results in a compile error in strict mode, or a TypeError at run time, because it attempts to assign a Vector.<Sprite> to a Vector.<DisplayObject> variable (Sprite is a subclass of DisplayObject):

     var v1:Vector.<Sprite> = new Vector.<Sprite>();
     v1[0] = new Sprite();
     var v2:Vector.<DisplayObject> = v1;
     

The following alternative version of the code successfully copies the elements of a Vector.<Sprite> instance to a Vector.<DisplayObject> instance:

     var v1:Vector.<Sprite> = new Vector.<Sprite>();
     v1[0] = new Sprite();
     var v2:Vector.<DisplayObject> = Vector.<DisplayObject>(v1);
     

Parameters

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Converts an object to an XML object.

The following table describes return values for various input types.

Parameters

Learn more

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Converts an object to an XMLList object.

The following table describes return values for various input types.

Parameters

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