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 <[EMAIL PROTECTED]> 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 ----- > *From:* Graham <[EMAIL PROTECTED]> > *To:* [email protected] > *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 <[EMAIL PROTECTED]> 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 > > > > > > > > ------------------------------------ > > > > Please note that this group is for discussion between users only. > > > > To get support from AmiBroker please send an e-mail directly to > > SUPPORT {at} amibroker.com > > > > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: > > http://www.amibroker.com/devlog/ > > > > For other support material please check also: > > http://www.amibroker.com/support.html > > Yahoo! Groups Links > > > > > > > > > > >
