Changing Y values in a chart

Here is the updated code:

开发者_Python百科private function myFillFunction(element:ChartItem, index:Number, item:Object,     
fieldName:String):IFill {
    var c:SolidColor = new SolidColor(0x00CC00);
    var ci:ColumnSeriesItem = ColumnSeriesItem(element);

    c.color = 0xFF2020;
    if ( Number(ci.yValue) >= 0 ) {
        c.color = 0x5586E0;
    } 

    if(fieldName == "yValue"){
        item.price= Math.abs( item.price);
    }
    else{
        item.date = item.date;
    }

    return c;
}

I get the following error: ArgumentError: Error #1063: Argument count mismatch on index/myFillFunction(). Expected 4, got 2.

you can get the absolute of a value much easier than what you are attempting by calling the abs() method of the Math class:

Math.abs(value);

however, the error is saying that you are trying to send 3 parameters to your fixNegatives(element:ChartItem) function while it can only receive the one ChartItem object.