Average (Arraylist function): Difference between revisions
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==Syntax== | ==Syntax== | ||
Revision as of 18:49, 10 July 2012
Average the members of this ArrayList (Arraylist class)
[Introduced in Sirius Mods 7.8]
Syntax
%average = al:Average[( [itemFunction])]
Syntax terms
| %average | A Float variable to contain the numeric result. |
|---|---|
| al | An Arraylist object. |
| method | A function that operates on the type of the items in the ArrayList. It may be a local method or method variable or a class member (Variable, Property), and it must return an intrinsic (probably Float) value.
The default method value is the special identity function, This, which simply returns the item value. |
Usage notes
- The optional method parameter lets you further manipulate the ArrayList item values
before performing the Average method's operation.
If your ArrayList's items are not intrinsic values, you must specify a function that can map the item values to intrinsic values or the method will fail.
For example, for an ArrayList that is a list of coordinates, you could return the average of their distance from the origin by first applying a local function as the Average method's method parameter:
b class point public constructor new(%x is float, %y is float) variable x is float variable y is float end public constructor new(%x is float, %y is float) %this:x = %x %this:y = %y end constructor end class local function (point):distance is float return (%this:x * %this:x + %this:y * %this:y):squareRoot end function %al is arrayList of object point %al = new %al:add(new(1,1)) %al:add(new(3,4)) %al:add(new(-5,12)) print %al:average(distance) end
The result is6.47140452079103.
Examples
b %al is arrayList of float %al = new %al:add(5) %al:add(3) %al:add(8) print %al:average end
The result is:
5.33333333333333