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Posted to user@velocity.apache.org by Tomasz Mielnik <to...@tdcinternet.pl> on 2003/01/29 09:04:14 UTC

selecting from foreach loop

hello 
i'm developing a webapp where i found the following problem:
i have foreach loop:

#foreach($log in $history)
 HTML HERE
#end

where $history is a java.util.Vector object.

my question is: how to make a loop in velocity which will behave like
for loop for example:
for (i=5; i<10; i++);
in other word how to select not all fields from vector but only a
specified range of them?
sorry if this subject was discused before, but i cant find it.

Tomasz Mielnik/Tdc Internet Polska






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Re: selecting from foreach loop

Posted by Ch...@dlr.de.
you can use the $velocityCount as others already replied in
this thread or you can use the range operator and the
java.util.Vector.get() method:
#for( $i in [5..10] )
   $history.get($i)
#end

I guess you want to display the last N lines, so you can try
to do (this is untested code out of my mind):
#set( $count = $history.size() )
#set( $from = $count - 10 )
#for( $i in [${from}..${count}] )
   $history.get($i)
#end

Velocity is cool! Hope this tip helped you on...

-- 
:) Christoph Reck

Tomasz Mielnik wrote:
> hello 
> i'm developing a webapp where i found the following problem:
> i have foreach loop:
> 
> #foreach($log in $history)
>  HTML HERE
> #end
> 
> where $history is a java.util.Vector object.
> 
> my question is: how to make a loop in velocity which will behave like
> for loop for example:
> for (i=5; i<10; i++);
> in other word how to select not all fields from vector but only a
> specified range of them?
> sorry if this subject was discused before, but i cant find it.
> 
> Tomasz Mielnik/Tdc Internet Polska

-- 
:) Christoph Reck


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Re: selecting from foreach loop

Posted by Tomasz Mielnik <to...@tdcinternet.pl>.
W liście z śro, 29-01-2003, godz. 09:18, Derick Fernando pisze: 
> Hello,
> 
> It would be best to limit the number of objects in your java class itself.
> But if you feel there is no other way, you could do something like:
> 
> in your Velocity.props file:
> 
> # Default name of the loop counter
> # variable reference.
> directive.foreach.counter.name = velocityCount
> 
> # Default starting value of the loop
> # counter variable reference.
> directive.foreach.counter.initial.value = 1
> 
> then you could do something like
> #foreach($log in $history)
>     #if( $velocityCount < 10)
>         HTML
>     #end
> #end
> 

thanks for help.
to be honest i did it exactly like this but i was looking for better
solutions and i must say that i like the idea with limiting number of
elements in vector.
thanks again
oh and btw: here is how i did it:

#foreach($log in $history)
  #set($counter=$velocityCount+$listcounter)
    #if($velocityCount>$listcounter &&     
	$velocityCount<$listlimit+$listcounter)
	HTML HERE
    #end
#end


Tomasz Mielnik


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Re: selecting from foreach loop

Posted by Derick Fernando <de...@xenocex.com>.
Hello,

It would be best to limit the number of objects in your java class itself.
But if you feel there is no other way, you could do something like:

in your Velocity.props file:

# Default name of the loop counter
# variable reference.
directive.foreach.counter.name = velocityCount

# Default starting value of the loop
# counter variable reference.
directive.foreach.counter.initial.value = 1

then you could do something like
#foreach($log in $history)
    #if( $velocityCount < 10)
        HTML
    #end
#end

( of course you could create a count variable as well, #set( $count = 0 ) )
etc..

Hope that helps,
Derick

----- Original Message -----
From: "Tomasz Mielnik" <to...@tdcinternet.pl>
To: <ve...@jakarta.apache.org>
Sent: Wednesday, January 29, 2003 12:04 AM
Subject: selecting from foreach loop


> hello
> i'm developing a webapp where i found the following problem:
> i have foreach loop:
>
> #foreach($log in $history)
>  HTML HERE
> #end
>
> where $history is a java.util.Vector object.
>
> my question is: how to make a loop in velocity which will behave like
> for loop for example:
> for (i=5; i<10; i++);
> in other word how to select not all fields from vector but only a
> specified range of them?
> sorry if this subject was discused before, but i cant find it.
>
> Tomasz Mielnik/Tdc Internet Polska
>
>
>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: velocity-user-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: velocity-user-help@jakarta.apache.org
>


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Re: selecting from foreach loop

Posted by Borja Martín <bm...@hola.com>.
try this:
#foreach($i in [3..6])
 $history.get($i)
#end 

it should work.

byez.
----- Original Message ----- 
From: "Tomasz Mielnik" <to...@tdcinternet.pl>
To: <ve...@jakarta.apache.org>
Sent: Wednesday, January 29, 2003 9:04 AM
Subject: selecting from foreach loop


> hello 
> i'm developing a webapp where i found the following problem:
> i have foreach loop:
> 
> #foreach($log in $history)
>  HTML HERE
> #end
> 
> where $history is a java.util.Vector object.
> 
> my question is: how to make a loop in velocity which will behave like
> for loop for example:
> for (i=5; i<10; i++);
> in other word how to select not all fields from vector but only a
> specified range of them?
> sorry if this subject was discused before, but i cant find it.
> 
> Tomasz Mielnik/Tdc Internet Polska
> 
> 
> 
> 
> 
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: velocity-user-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: velocity-user-help@jakarta.apache.org
> 
> 


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RE: selecting from foreach loop

Posted by Andy Lee <ag...@earthlink.net>.
At 1:13 PM +0100 1/29/03, Tomasz Mielnik wrote:
>W liÊcie z Êro, 29-01-2003, godz. 10:49, Peter Romianowski pisze:
>
>  > #foreach ($pos in [5..9])
>  >     $history.get($pos)
>  > #end
>

One caveat: in loops through integer ranges, Velocity always iterates 
at least once.  It counts by -1 instead of 1 if the last number is 
smaller than the first number.  So if $history is empty, the 
following innocent-looking loop will generate an 
ArrayOutOfBoundsException instead of doing nothing:


#set( $lastIndex = $history.size() - 1 )
#foreach ($pos in [0..$lastIndex])
     $history.get($pos)
#end


--Andy

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RE: selecting from foreach loop

Posted by Tomasz Mielnik <to...@tdcinternet.pl>.
W liście z śro, 29-01-2003, godz. 10:49, Peter Romianowski pisze: 

> #foreach ($pos in [5..9])
>     $history.get($pos)
> #end

what can i say :) 
sweeet. it's simply and it works.
thanks a lot.

Tomasz Mielnik



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RE: selecting from foreach loop

Posted by Peter Romianowski <me...@gmx.de>.
Tomasz,

> hello 
> i'm developing a webapp where i found the following problem:
> i have foreach loop:
> 
> #foreach($log in $history)
>  HTML HERE
> #end
> 
> where $history is a java.util.Vector object.
> 
> my question is: how to make a loop in velocity which will 
> behave like for loop for example: for (i=5; i<10; i++); in 
> other word how to select not all fields from vector but only 
> a specified range of them? sorry if this subject was discused 
> before, but i cant find it.

#foreach ($pos in [5..9])
    $history.get($pos)
#end

is the same as in java: for (pos = 5; pos < 10; pos++)
 
> Tomasz Mielnik/Tdc Internet Polska

Peter


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