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Wolfgang,
That was an excellent explanation and it helps a
lot.
I had assumed that passing two arrays through a
boolean test would automatically give a boolean result since the test was on a
boolean basis.
The explanation of the stored result actually
being an array of float vs. array of boolean is what I needed.
Thanks to all who helped!
-CS
<BLOCKQUOTE
>
----- Original Message -----
<DIV
>From:
Wolfgang Schwendt
To: <A title=amibroker@xxxxxxxxxxxxxxx
href="">amibroker@xxxxxxxxxxxxxxx
Sent: Tuesday, May 27, 2003 2:09 PM
Subject: [amibroker] Re: Boolean
question
Hello,Like many scripting languages, AFL is a
loosely typed language, whichmeans in computer science parlance that you
don't have to explicitlydeclare the type of your variables before you use
them. The type of avariable is automatically inferred from the type of the
expressionsassigned to that variable.The advantage is that scripts
can be written in just a few lines ofcode, without any formal variable
declarations being required. This disadvantage is that sometimes
the meaning (semantic) of scriptscan become more difficult to
understand. For example, it can be muchmore difficult to see quickly
what the type of a variable is.> T1=20;>
Z1=BarIndex()>T1;> > Does Z1 contain a boolean
response?> I'm still new to AFL, but my understanding of the
example given in thequestion would be as follows:BarIndex()
returns an Array (as per the AB help).Hence also the "greater than"
operator '>' returns an array. Itcompares the elements of
the BarIndex()-array element-wise with 20. In the result array either 0 or
1 is stored is stored for eachelement-wise comparison respectively,
with 0 indicating false and 1indicating true. The
result array is an array of float numbers, soits type is actually "array
of float" and not "array of boolean".If I'm not mistaken, AFL
has actually not any real boolean variables.It interprets a float value of
0 as false, and a float value not equalto 0 as true.So the answer
to the question is: Z1 is an array of float values.> Anyone know
how to convert Z1 to boolean?in order to convert Z1 to a boolean value
(actually a float value),you need to reference a specific element of the
arrayThis can be done with the array access operator '[]', e.g. with
anexpression like result[i], with i specifying the index of the
arrayelement you want to refer to.Hope it
helps,WolfgangSend
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