Format Decimal

Function: string FormatDecimal(float number, integer precision);

Formats a float value to a fixed precision ie. for display purposes

Returns a string that comprises the number truncated and rounded to the given precision.

• float	number	–	any valid float, positive or negative
• integer	precision	–	precision of result. Positive values truncate fraction, negative values truncate integer part of number

precision	Value
positive	Truncates number rounded to this fraction positions
zero	Truncates number rounded to it's integer value
negative	Rounds number at this pre-decimal position

Specification

string FormatDecimal(float number, integer precision)
{    
    float roundingValue = llPow(10, -precision)*0.5;
    float rounded;
    if (number < 0) rounded = number - roundingValue;
    else            rounded = number + roundingValue;
    
    if (precision < 1) // Rounding integer value
    {
        integer intRounding = (integer)llPow(10, -precision);
        rounded = (integer)rounded/intRounding*intRounding;
        precision = -1; // Don't truncate integer value
    }
    
    string strNumber = (string)rounded;
    return llGetSubString(strNumber, 0, llSubStringIndex(strNumber, ".") + precision);
}

Examples:

number	precision	Result	Source
123.456	2	123.46	FormatDecimal(123.456, 2)
-123.456	2	-123.46	FormatDecimal(-123.456, 2)
123.456	0	123	FormatDecimal(123.456, 0)
123.456	-2	100	FormatDecimal(123.456, -2)

Caveats

Maximum value is restricted to integer range, that is -2,147,483,648 to +2,147,483,647

Example

Trivial example to listen to any chat from the object owner for number, precision values and respond formatted value.

string FormatDecimal (float number, integer precision)
{    
    float roundingValue = llPow(10, -precision)*0.5;
    float rounded;
    if (number < 0) rounded = number - roundingValue;
    else            rounded = number + roundingValue;
    
    if (precision < 1) // Rounding integer value
    {
        integer intRounding = (integer)llPow(10, -precision);
        rounded = (integer)rounded/intRounding*intRounding;
        precision = -1; // Don't truncate integer value
    }
    
    string strNumber = (string)rounded;
    return llGetSubString(strNumber, 0, llSubStringIndex(strNumber, ".") + precision);
}

default
{
    state_entry()
    {
        llOwnerSay("Enter: [number,precision]");
        llListen(0, "", llGetOwner(), "");
    }

    listen(integer _chan, string _str, key _id, string _msg)
    {
        list values=llCSV2List(_msg);
        float number = llList2Float(values,0);
        integer decimals = llList2Integer(values,1);
        llOwnerSay("Number " + (string)number + " is formatted " + FormatDecimal(number, decimals));
    }
}