you could try this, and explore on n=1 last quotation
inTrade =
flip(buy,sell);
filter = inTrade;
addcolumn(valuewhen(buy,datetime()),"Buy
Date",formatdatetime);
--
Cheers
Graham
Kav
AFL Writing Service
http://www.aflwriting.com
On 20/04/2008, Brian
Wild <wild21@xxxxxxxxxcom.au>
wrote:
Thanks Graham for the response - but what you
suggest is what I first tried. The only difference is that I used the
variable "bought" where you used "InTrade". In trying to sort this out I
have come across a really puzzling result. I used AddColumn to show results
for Buy, Sell, and bought. Then, changing only the filter value gives the
following:-
Case A. Setting Filter = Buy or Sell, gives
output lines (correctly) only where there is a buy or sell
signal.
Case B. Setting Filter = 1 gives an output for
every data point, with Buy and Sell still showing up as 1 correctly where
they should, and bought showing correctly as 1 following each buy and
remaining there until resetting to zero at the next sell. (so far so
good!).
Case C. Setting Filter = bought STILL gives
output for every data point (incorrect!?). Buy and Sell still show 1
where they should, but bought now shows as 1
throughout.
I guess that with bought set to 1 throughout I
should expect output for every data point - BUT how can this have happened
in the circumstances. if anyone can explain I would be most
grateful!
Brian W
-----
Original Message -----
Sent:
Sunday, April 20, 2008 2:49 PM
Subject:
Re: [amibroker] Simple Exploration Question
you could try a few things, but this is probably the
easiest
inTrade = flip(buy,sell);
filter =
inTrade;
--
Cheers
Graham Kav
AFL Writing Service
http://www.aflwriting.com
On 20/04/2008,
brianboofhead <wild21@xxxxxxxxxcom.au> wrote:
>
Hi,
> Hope someone can help with this simple problem.
> I have
a system which generates Buy and Sell signals, and have used
> Exrem
to remove excess signals. I now want to run an exploration over
>
all symbols in my database to select all those for which the last
>
signal was a Buy. I realise I could use Explore over the last n
days
> (n=50 say)to pick up buy signals but would prefer to run over
all
> quotations and pick up the last Buy, regardless of how long
ago that
> was.
> I tried adding:-
> bought = flip(buy,
sell); which sets bought to 1 after the last buy if
> there is no
subsequent sell.
> Also used Addcolumn to display bought.
>
However, testing on a single stock with various attempts to filter
on
> the LastValue of bought didn't work, as the Explore output gave
every
> value in the chosen stock. My attempts to use ValueWhen(bi =
Barcount)
> fared no better.
> The problem (to me at least)
seems to be that when you would like to
> set a single variable to a
value, AFL makes it a complete array. The
> reason for this
long-winded question is that I think this problem of
> getting
single values rather than arrays arises all the time - so a
>
general explanation of ways around it would be most helpful.
>
Thanks in anticipation
>
> Brian
W
>
>
>
>
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