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Re: [amibroker] Re: Finding the last true value in an array...



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hi,
 
you could shift the array.
 
for instance jj1 is an array with 1 and 0
 
then:
 
// calculate bars since last occurunce of 1
kk1 =
BarsSince
(jj1);
// shift jj by that amount and so remove the last occurrence of 1, save result in jj2

jj2 =
Ref(jj1,-LastValue(kk1)-1
);
// now shift jj2 back by that amount and save in jj3

jj3 =
Ref(jj2,LastValue(kk1)+1
);
// now calculate bars since the prior to last occurence of 1

kk2 =
BarsSince
(jj3);
WriteVal
(kk1);
WriteVal
(kk2);
 
rgds, Ed
 
 
 
----- Original Message -----
Sent: Tuesday, January 13, 2009 3:28 PM
Subject: [amibroker] Re: Finding the last true value in an array...

Well lets just look at a pretend array... I think that puts it in its
simplest context....

Effectively what I'm trying to do is replicate EXACTLY the
functionality of BarsSince() but instead of starting from the most
current array element and moving backwards, I want to start a
specified number of intervals back and move forward...

Obviously when you use BarsSince() it returns an array... in the same
way, I'd like my function to return an array. Looking at this example,
ans assuming that the array before x simply has zeros in it...

0,1,0,0,0,0,0,1,0,0
x.................Now

BarsSince(array) would produce (I think),

0,0,1,2,3,4,5,0,1,2

I want a function that will work from x to Now, and return,

0,0,1,2,3,4,5,6,7,8

I can do this with a loop obviously (but I hate loops). This is a
problem I've hit before. I'd just love to know if there's an array
solution...

TIA

--- In amibroker@xxxxxxxxxps.com, "wavemechanic" <timesarrow@...> wrote:
>
> Don't have time now to think about it and it would be easier if you
posted the code instead of working with a moving target. However, off
the top of my head you might be able to avoid looping by using brute
force. For example, if the range is 5 bars then you could test the
5th bar back with iif(barssince(x) == 5, and if that is negative then
do the same for the 4th bar back, etc.
> ----- Original Message -----
> From: sidhartha70
> To: amibroker@xxxxxxxxxps.com
> Sent: Tuesday, January 13, 2009 8:04 AM
> Subject: [amibroker] Re: Finding the last true value in an array...
>
>
> SelectedValue() works Bill... Thanks.
>
> However, the problem I'm having is that I'm using this in AFL code and
> I want it to complete the historical array if you like, not just off a
> SelectedValue() but with each value of Sum(x,range) as ir changes...
> which it's looking like is not possible.
>
> Horribly I might have to use a loop. Errrgg.
>
> --- In amibroker@xxxxxxxxxps.com, "sidhartha70" <sidhartha70@> wrote:
> >
> > Nope, I've tried it Bill...
> >
> > I get an Error 5, Argument #3 has incorrect type on the ValuneWhen()
> > line...
> >
> >
> >
> > --- In amibroker@xxxxxxxxxps.com, "wavemechanic" <timesarrow@>
wrote:
> > >
> > > Have you tried it or are just "not sure"? Works for me and
can move
> > to any bar and get the "selectedvalue". If in doubt use
> > selectedvalue(sum()).
> > > ----- Original Message -----
> > > From: sidhartha70
> > > To: amibroker@xxxxxxxxxps.com
> > > Sent: Tuesday, January 13, 2009 6:01 AM
> > > Subject: [amibroker] Re: Finding the last true value in an
array...
> > >
> > >
> > > Actually Bill, not sure this works... since the 3rd argument in
> > > ValueWhen() is required to be a number and not an array.
> > > Could use LastValue() to turn it into a number, but of
course this
> > > only returns the value from the right hand edge of the chart...
> so it
> > > wouldn't work historically... which is what I need.
> > >
> > > Any thoughts...?
> > >
> > > --- In amibroker@xxxxxxxxxps.com, "wavemechanic" <timesarrow@>
> wrote:
> > > >
> > > > How about this?
> > > >
> > > > x = condition that generates your 1,0 array
> > > > y = sum(x, range)
> > > > z = valuewhen(x, barindex(), y)
> > > > position in array = lastvalue(barindex()) - z + 1
> > > >
> > > > Bill
> > > > ----- Original Message -----
> > > > From: sidhartha70
> > > > To: amibroker@xxxxxxxxxps.com
> > > > Sent: Monday, January 12, 2009 6:33 PM
> > > > Subject: [amibroker] Re: Finding the last true value in an
> > array...
> > > >
> > > >
> > > > Sorry Barry... my terminology is confusing...
> > > >
> > > > Lets say I have an array that has only true or false
values in
> > it...
> > > >
> > > > Lets say the last 10 value of this array are as follows,
from x
> > > > intervals ago until now...
> > > >
> > > > 0,1,0,0,1,0,0,1,0,0
> > > > x.................Now
> > > >
> > > > Now, obviously, BarsSince(array) will return a value of 2...
> > i.e. the
> > > > last true value was 2 intervals ago.
> > > >
> > > > However, the value I'm trying to get is the last value
of true
> > in the
> > > > above x elements of the array... so I want an _expression_
that
> > returns
> > > > 8 for the above array (i.e. 8 intervals back is the last
> value of
> > > > true). Any ideas...?
> > > >
> > > > Hopefully that's clearer now.
> > > >
> > > >
> > > > --- In amibroker@xxxxxxxxxps.com, "Barry Scarborough"
> <razzbarry@>
> > > > wrote:
> > > > >
> > > > > What are your trying to do? HHV gives the value of the
> > highest high
> > > > > over the period you enter in x. If you want to find how
> far back
> > > that
> > > > > is you can use
> > > > >
> > > > > bs = BarsSince(H == HHV(H, 10));
> > > > > // the next line prints the num bars back and the high of
> > that bar
> > > > > printf(NumToStr(bs, 1.0) + " High " + NumToStr(HHV(H, 10),
> > 1.2));
> > > > >
> > > > > If you want to find the value of the other things bs bars
> > ago then
> > > > > you can
> > > > > // use the following. This applies to any array
> > > > > lastHigh = ref(High, - bs);
> > > > > // this is another way to see the results that shows the
> > high value
> > > > > Plot(lastHigh, "high bars ago", colorBlack);
> > > > > Plot(Ref(C, -bs), "close bars ago", colorblue);
> > > > > Plot(Ref(MA(C, 10), -bs), "MA(10) value bars ago",
> colorGreen);
> > > > > // then look at what valuewhen returns
> > > > > Plot(ValueWhen(H == HHV(H, 10), H, -1), "ValueWhen",
> colorRed);
> > > > >
> > > > > bsolutely the last thing you want to do is start using
loops,
> > > such as
> > > > > for loops, to extract data from ABs arrays. Your code will
> > be much
> > > > > cleaner and faster if you use straight AFL.
> > > > >
> > > > > Your terminology true value is confusing. The value in an
> > array is
> > > > > the true value. Do you mean what was the value when the
> > > condition was
> > > > > true?
> > > > >
> > > > > Barry
> > > > >
> > > > >
> > > > >
> > > > > --- In amibroker@xxxxxxxxxps.com, "sidhartha70"
> <sidhartha70@>
> > > > > wrote:
> > > > > >
> > > > > > Graham,
> > > > > >
> > > > > > I'm trying to get my head around that code right now...
> > but first
> > > > > > thing I noticed was that my post was poorly worded.
Let me
> > > reword it
> > > > > > below, and maybe you can tell me if this is what you
> > thought I
> > > > > meant....
> > > > > >
> > > > > > Ok. It's easy to find the first occurrence of a true
value
> > of an
> > > > > > array... that is looking from now backwards x intervals.
> > simply
> > > > > > HHV(array,x) where x=no of intervals back.
> > > > > >
> > > > > > However, how can I find the last true value of the array
> > looking
> > > > > back
> > > > > > over x intervals...?? i.e. the first true value starting
> from
> > > x and
> > > > > > looking forward to now.
> > > > > >
> > > > > > is there an array method without looping...?
> > > > > >
> > > > > > Many Thanks
> > > > > >
> > > > > >
> > > > > > --- In amibroker@xxxxxxxxxps.com, Graham <kavemanperth@>
> > wrote:
> > > > > > >
> > > > > > > try this
> > > > > > > array = h;
> > > > > > > LastHHVValue = valuewhen( hhvbars(array,x)==0,
array );
> > > > > > >
> > > > > > > --
> > > > > > > Cheers
> > > > > > > Graham Kav
> > > > > > > AFL Writing Service
> > > > > > > http://www.aflwriting.com
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 2009/1/13 sidhartha70 <sidhartha70@>:
> > > > > > > > Hi All,
> > > > > > > >
> > > > > > > > Ok. It's easy to find the last true value of an
array...
> > > simply
> > > > > > > > HHV(array,x) where x=no of intervals back.
> > > > > > > >
> > > > > > > > However, how can I find the last true value of the
> array
> > > > > looking back
> > > > > > > > over x intervals...??
> > > > > > > >
> > > > > > > > is there an array method without looping...?
> > > > > > > >
> > > > > > > > Many Thanks
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > ------------------------------------
> > > >
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>
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> > > >
> > > >
> > > > No virus found in this incoming message.
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> > > > Version: 8.0.176 / Virus Database: 270.10.6/1889 -
Release Date:
> > > 1/12/2009 8:18 PM
> > > >
> > >
> > >
> > >
> > > ------------------------------------
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> > > **** IMPORTANT ****
> > > This group is for the discussion between users only.
> > > This is *NOT* technical support channel.
> > >
> > > *********************
> > > TO GET TECHNICAL SUPPORT from AmiBroker please send an e-mail
> > directly to
> > > SUPPORT {at} amibroker.com
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----------------------------------------------------------
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> > >
> > >
> > > No virus found in this incoming message.
> > > Checked by AVG - http://www.avg.com
> > > Version: 8.0.176 / Virus Database: 270.10.6/1891 - Release Date:
> > 1/13/2009 8:17 AM
> > >
> >
>
>
>
> ------------------------------------
>
> **** IMPORTANT ****
> This group is for the discussion between users only.
> This is *NOT* technical support channel.
>
> *********************
> TO GET TECHNICAL 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
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>
>
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----------------------------------------------------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com
> Version: 8.0.176 / Virus Database: 270.10.6/1891 - Release Date:
1/13/2009 8:17 AM
>

__._,_.___

**** IMPORTANT ****
This group is for the discussion between users only.
This is *NOT* technical support channel.

*********************
TO GET TECHNICAL 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

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