Scan Confusion

JJJJ
JJJJ ✭
in Scanning
I was writing a scan to compare absolute values of daily lows and highs. I wrote this scan and clicked on check syntax....and it came back with YOUR SCAN SYNTAX IS CORRECT ! How can this occur with one less right hand bracket in the third line vrs the second line ? Enter the statements below as a scan and see for yourself.

[type = stock] AND [Daily SMA(20,Daily Volume) >200000]
and [[AbsVal(high)- AbsVal(low)]< [AbsVal(1 day ago high)- AbsVal(1 day ago low)]]
and [[AbsVal(high)- AbsVal(low)]< [AbsVal(2 day ago high)- AbsVal(2 day ago low)]

Any thoughts ?

Thanks,

JJ
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Comments

  • markd
    markd mod
    edited July 2018
    I get a syntax error for mismatched square brackets. I don't know why you would have gotten an 'ok' message. It's possible you "mis-clicked" somehow (e.g. the cursor wasn't where you thought it was, or you left-clicked instead of right-clicked, or...) so you didn't actually send the revision and the 'ok' message was left over from the previous successful check because the screen didn't refresh. But, I'm just guessing.

    I do have a question about the scan, however.

    Your parameters inside your absval function - high, low, 1 day ago high, 1 day ago low - are all positive numbers, so the absval function is unnecessary.

    Maybe you were thinking of:

    and [absval(high - low) < absval( 1 day ago high - 1 day ago low)]

    but, high - low will always be a positive number also (or sometimes 0), so absval is not necessary there either.

    I think what you want is:

    and [range < 1 day ago range]
    and [range < 2 days ago range]

    or, you could also write

    and [range = min(3, range)]

    although that is slightly different, in that two - or all three - values could be equal and the most recent would still be the min 3.



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