I was doing some bill calculations, and went looking in the math method for an average.

Usage would be something like

• math.average(1, 4, 6, 7, 8, 9)
• math.average(ListOfIntegers)
• math.average(ListOfDecimals)

or same type of stuff with sets.

Spent about 15 minutes looking and googling. I know about SOQL aggregate, but this is lots of calc with lots of intermediate steps.

This must exist, right?

Attribution to: Shane McLaughlin

Possible Suggestion/Solution #1

Unfortunately the standard math methods only include simpler operations (i.e. those that work on a single, or two values), so it looks as though you'll have to roll your own method.

Of course the number of script statements executed will be proportional to the length of the list, so of the lists are ever of a fixed size it could be worth using a macro to generate the addition part for you:

Int sum = i[0] + i[1] + ... i[n];

Doing so would only count for one statement, but you'll only need this if governor limits are of concern which is often not a worry.

If govenor limits aren't an issue you could create a function along these lines:

Integer[] myInts = new Integer[]{1, 2, 3, 4, 5, 6, 7};
Integer total = 0;
Double dAvg;

for (Integer i : myInts) {
    total += i;
}

dAvg = Double.valueOf(total) / myInts.size();

return dAvg;

Attribution to: Matt Lacey

Possible Suggestion/Solution #2

I have a small statistical library on github. It provides various measures of centrality and dispersion, including Stats.mean:

public static Decimal mean(List<Decimal> nums) {
    Decimal total = 0.0;
    for (Decimal n : nums) {
        total += n;
    }
    return total / nums.size();
}

Attribution to: ipavlic
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