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Hi Dave, thanks for the compliment - I saw a few typos so I made some quick changes - have at it!
Steve
In "regular" AFL, all elements of the data arrays are automatically processed at once. So for example
Close = 0;
will automatically initialize the entire Close array ( all dates ) by setting all of its elements to zero ( or more precisely, a working copy of Close, since actual database is not overwritten ). In general, it is quicker and easier to use this regular AFL - loops are really only necessary when you need to access individual array elements for some reason. A simple loop "template" would be
for ( set beginning counter value; test for condition(s) to break out of loop; increment counter )
{
code to do whatever you want to current array element
}
Now we will turn the template into a real loop. "i" is simply a variable that accepts a numeric value and acts as a counter. We will increment it with each pass through the loop to keep track of where we are in the array. The letter "i" is commonly used for this because, I beleive, it stands for "integer", but we can actually use any variable name we want, such as "count", etc
for( count = 0; count < BarCount; count++ )
{
Close[count] = 0;
}
This also initializes the Close array to zero, just like the "regular" AFL above, but one element at a time. As you can see, using regular AFL is easier 8 - ) Now we will "pick apart" the loop a bit...
for ( count = 0
Since we want to start with the first array element ( element # 0 ), we initialize the counter at 0. The loop reads this code just once at the beginning to see which array element to start at, it will not be rechecked after the loop starts running.
count < Barcount
BarCount is the number of data bars for any given ticker. Lets say it is 1000, so the actual elements of the Close array would be numbered 0 - 999.
"count < Barcount" tests to see if it is time to stop looping yet. It means "continue doing loops while count is less than Barcount." Since we have just set "count" to 0, it is less than 1000 so the loop will be entered.
{
Close[count] = 0;
}
This is the "body" of the loop - it contains the instructions to be performed on each pass through the loop. Here we are just initializing a single element of the Close array to 0. On this pass, the variable "count" is set to 0, so Count[0] ( first element ) will be set to 0.
count++ ) // back up to the header now
This is just a short way of writing "count = count + 1". We are just incrementing the count by one. When we are incrementing by 1, we are allowed to use this "shorthand". If we were incrementing by anything else, like 2 or 3, we would have to write "count = count + 2", etc. So next, count is incremented from 0 to 1.
Now, the first pass is done, and subsequent passes will continue repeating the same above steps until the end of the array is reached -
1. Is count still < Barcount? If so, do another pass through loop, if not, time to exit the loop.
2. If doing another pass, set Close[count] ( next element ) to 0
3. increment counter again so next element is accessed on next pass
----- Original Message -----
From: MarketMonk777
To: amibroker@xxxxxxxxxxxxxxx
Sent: Monday, July 24, 2006 11:05 AM
Subject: RE: RE: RE: [amibroker] Re: I am lostII
Steve,
An outstanding explaination. Thanks for taking the time to put it together.
Dave
I think it is good enough to be converted to a PDF and uploaded so it can be pointed to in the future. I would be glad to do so unless you want to tweak it somemore.
------------------------------------------------------------------------------
From: amibroker@xxxxxxxxxxxxxxx [mailto:amibroker@xxxxxxxxxxxxxxx] On Behalf Of Steve Dugas
Sent: Monday, July 24, 2006 7:09 AM
To: amibroker@xxxxxxxxxxxxxxx
Subject: Re: RE: RE: [amibroker] Re: I am lostII
Hi Allen - Here are the basics of a simple loop, hope it is helpful to someone...
In "regular" AFL, all elements of the data arrays are automatically processed at once. So for example
Close = 0;
will automatically initialize the entire Close array ( all dates ) by setting all of its elements to zero ( or more precisely, a working copy of Close, since actual database is not overwritten ). In general, it is quicker and easier to use this regular AFL - loops are really only necessary when you need to access individual array elements for some reason. A simple loop "template" would be
for ( beginning counter value; test for condition(s) to break out of loop; increment counter )
{
code to do whatever you want to current array element
}
Now we will turn the template into a real loop. "i" is simply a variable that accepts a numeric value and acts as a counter. We will increment it with each pass through the loop to keep track of where we are. The letter "i" is commonly used for this because, I beleive, it stands for "integer", but we can actually use any variable name we want, such as "count", etc
for( count = 0; count < BarCount; count++ )
{
Close[count] = 0;
}
This also initializes the count array to zero, but one element at a time. As you can see, using regular AFL is easier 8 - ) Now we will "pick apart" the loop a bit...
for ( count = 0
Since we want to start with the first array element ( element # 0 ), we initialize the counter at 0. The loop reads this code just once at the beginning to see where to start, it will not be rechecked after the loop starts running.
count < Barcount
BarCount is the number of data bars for any given ticker. Lets say it is 1000, so the actual elements of the Close array would be numbered 0 - 999.
"count < Barcount" tests to see if it is time to stop looping yet. It means "continue doing loops while count is less than Barcount." Since we have just set "count" to 0, it is less than 1000 so the loop will be entered.
{
Close[count] = 0;
}
This is the "body" of the loop - it contains the instructions to be performed on each pass through the loop. Here we are just initializing a single element of the Close array to 0. On this pass, the variable "count" is set to 0, so Count[0] ( first element ) will be set to 0.
count++ ) // back up to the header now
This is just a short way of writing "count = count + 1". We are just incrementing the count by one. When we are incrementing by 1, we are allowed to use this "shorthand". If we were incrementing by anything else, like 2 or 3, we would have to write "count = count + 2", etc. So next, count is incremented from 0 to 1.
Now, the first pass is done, and subsequent passes will continue repeating the same above steps until the end of the array is reached -
1. Is count still < Barcount? If so, do another pass through loop, if not, time to exit the loop.
2. If doing another pass, set Close[count] ( next element ) to 0
3. increment counter again so next elent is accessed on next pass
If this sounds too simplstic or condescending, I apologize. Or, if you have any questions, feel free to ask...
Steve
----- Original Message -----
From: allansn@xxxxxxxxxxxxx
To: amibroker@xxxxxxxxxxxxxxx
Sent: Sunday, July 23, 2006 10:52 PM
Subject: Re: RE: RE: [amibroker] Re: I am lostII
Hi Dingo,
I have no problem doing anything along the lines of powerscan and writing code.Ami is excellent and intuitive as far as that...
The problem for a complete non programmer is when i get to "looping",the manuals tend to leave out thebasic steps....its little things like the "i" and "{ " and " = = " and "buy=0" that are difficult to figure out.I get the intended logic,its just tought to build on having no foundation...
Appreciate it
Allan
----- Original Message -----
From: dingo <dingo@xxxxxxxxxxxx>
Date: Sunday, July 23, 2006 10:44 pm
Subject: RE: RE: [amibroker] Re: I am lostII
> Its Powerscan: http://www.amitools.com/
>
> d
>
>
> _____
>
> From: amibroker@xxxxxxxxxxxxxxx [mailto:amibroker@xxxxxxxxxxxxxxx]
> On Behalf
> Of Terry
> Sent: Sunday, July 23, 2006 8:47 PM
> To: amibroker@xxxxxxxxxxxxxxx
> Subject: RE: RE: [amibroker] Re: I am lostII
>
>
>
> See Steve's reply because the big difference in AFL is the array
> processingas Steve explained.
>
>
>
> The books were for Excel VBA programming (macros) because that's
> what you
> asked for. VBA is, in a way, quite similar to AB when using loops.
> They are
> just constructed a little different. I learned Basic programming
> first, then
> VBA (which is also a variation of BASIC). I picked up AFL from
> there with a
> little intro by an experienced trader and then just doing it,
> reading help
> files and asking a few questions along the way.
>
>
>
> Just look at some of the basic formulas you find in AB charts or the
> library. Take the ones that don't look too complicated and
> understand them.
> Change a few things. You'll be surprised at what you can learn.
> There is
> also (someone please help here) an automated AFL code writer. You
> tell it
> your rules and it writes code. You can then see what it did.
>
> --
>
> Terry
>
> -----Original Message-----
> From: amibroker@xxxxxxxxxxxxxxx [mailto:amibroker@xxxxxxxxxxxxxxx]
> On Behalf
> Of allansn@xxxxxxxxxxxxx
> Sent: Sunday, July 23, 2006 13:35
> To: amibroker@xxxxxxxxxxxxxxx
> Subject: Re: RE: [amibroker] Re: I am lostII
>
>
>
> Hi Terry,
>
> Noticed you reccomended these 2 books...I have absolutely no
> problem coding
> in Amibroker,but I do run into problems with coding such as this..
>
> for( i = 0; i < *BarCount*; i++ )
> {
> if( priceatbuy == 0 *AND* *Buy*[ i ] )
>
> {
> priceatbuy = *BuyPrice*[ i ];
>
>
>
> How would one become proficient/knowledgable in writing code such
> as this???
>
> Is this AFL??? or
>
> Is this sort of language inherent in every language?
>
> Would either of the 2 books you reccomended assist me in this task?
>
> If you or anyone could point me in the direction of a "Dummies "
> book,thatwould be great.I would just like to be proficient at
> writing/understandingcode such as the snippet above
>
>
>
> Someone reccomended Beggining Programming for Dummies by Wang...
>
>
>
> Any thoughts deeply appreciated
>
>
>
> Allan
>
>
>
>
>
>
>
>
>
>
>
> ----- Original Message -----
>
> From: Terry <MagicTH@xxxxxxxxxxx>
>
> Date: Sunday, July 16, 2006 9:34 pm
>
> Subject: RE: [amibroker] Re: I am lost
>
> > Great book for macro and function coding:
> > http://www.wrox.com/WileyCDA/WroxTitle/productCd-0764543717.html
> >
> > Excel for Dummies:
> > http://www.amazon.com/gp/product/1568840500/sr=1-
> > 1/qid=1153099963/ref=sr_1_1/104-1895807-1075905?ie=UTF8&s=books
> >
> >
> >
> > --
> >
> > Terry
> >
> > -----Original Message-----
> > From: amibroker@xxxxxxxxxxxxxxx
> [mailto:amibroker@xxxxxxxxxxxxxxx] On
> > Behalf Of MillowenaJuno
> > Sent: Sunday, July 16, 2006 08:36
> > To: amibroker@xxxxxxxxxxxxxxx
> > Subject: Re: [amibroker] Re: I am lost
> >
> >
> >
> > Hi Ton!
> >
> >
> >
> > Is there a Programming Excel for Dummies?
> >
> >
> >
> > Thanks!
> >
> >
> >
> > Millowena
> >
> >
> >
> >
>
>
>
>
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