Performance vs. SPX Since Earnings

[flyer01]

Is it possible to create a scan that return stocks that have outperformed SPX x% since the stock's last earnings date. Here's how I would envision it working:

1. Determine the number of bars ago since the last earnings date using a function like HasEarnings(). I'm not sure how that number would be stored.
2. Determine the % change between the close on the current bar and the bar identified in #1.
3. Determine the % change of the SPX over the same period as #2.
4. Determine the variance between the stock's performance vs. the SPX performance over that period.

I'd appreciate it if someone could help provide a starter script, especially for #1 and #3 above. Thank you!

 

[Joshua]

input Sym = "SPX";
input OutPerf = 3;

def Earn =
    hasearnings();
def eP =
    if Earn then Close
    else eP[1];
def iP =
    if Earn then Close(SYM)
    else iP[1];
plot eC =
    (Close - eP) / eP * 100;
plot iC =
    (Close(SYM) - iP) / iP * 100;
plot Diff =
    eC - iC;
plot Scan =
    Diff >= OutPerf;
diff.assignValueColor(
    if Diff >= OutPerf then color.green
    else color.red);
#######
plot z = OutPerf;
addverticalLine(Earn or Earn[1]);
addlabel(yes," " + getsymbol() + " " ,eC.takeValueColor());
addlabel(yes," " + Sym + " ",iC.takeValueColor());
addlabel(yes," Diff ",Scan.takeValueColor());
declare lower;

This should contain everything you need to get started. To make it a scan, you only need to ensure that you're scanning based on the plot named "scan." Or for simplicity, change out all of the other plots to Def, and the stuff at the bottom can be deleted.