Interpolation in a hash key

pickledegg has asked for the wisdom of the Perl Monks concerning the following question:

I have the following code, I want to run it 20 times in a loop and replace all the occurences of number'1's in the $hashRecordPtr's with the $count variable.
I'm stuck with the syntax for this.
Can someone please help me at all? It will save me a few hundred lines of code if I can understand this one. :-)

$count=0;
while ($count < 20){

$count+=1;
if ($$hashRecordPtr{'price_product1'} ne "" )  {
print "<tr bgcolor=\"#EDEFF5\">"; 
if ($$hashRecordPtr{'connection1_description'} ne ""){
print<<"CONNECTION1";
<td valign="middle" align="center" width="78">$$hashRecordPtr{'connect
+ion1_size1'}</td> 
CONNECTION1
}
if ($$hashRecordPtr{'connection1_description'} ne ""){
print<<"CONNECTION2";
<td width="78" align="center" valign="middle">$$hashRecordPtr{'connect
+ion2_size1'}</td>
CONNECTION2
}

print "<td width=\"78\" align=\"center\" valign=\"middle\">$$hashRecor
+dPtr{'part_number1'}</td>";
if ($$hashRecordPtr{'part_reference1'} ne ""){ # ie its a pack not ind
+.
print<<"PARTREF";
<td width="78" align="center" valign="middle">$$hashRecordPtr{'part_re
+ference1'}</td>
PARTREF
}
if ($$hashRecordPtr{'pack_qty1'} > 2){ # ie its a pack not ind.
print<<"PACK";
<td width="78" align="center" valign="middle">$$hashRecordPtr{'pack_qt
+y1'}</td>
PACK
}
print<<"HTML3";
<form name="prod_1" action="shoppingBasket2.cgi" method="post">
<td width="68" align="center" valign="middle">&pound;$$hashRecordPtr{'
+price_product1'}</td>
<td width="72" align="center">
<select name="order_qty">
<option value="1" selected>1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
<option value="9">9</option>
<option value="10">10</option>
</select>
</td>
<td width="98" align="center" bgcolor="#EDEFF5"><a href=\"javascript: 
+validateUserAdd(prod_1)\">Add To Basket</a></td>
<input type="hidden" name="action" value="add">
<input type="hidden" name="product_id" value="$$hashRecordPtr{'product
+_id'}">
<input type="hidden" name="product_details" value="$$hashRecordPtr{'sh
+ort_details'} ($$hashRecordPtr{'code1'})">
<input type="hidden" name="code" value="$$hashRecordPtr{'code1'}">
</tr>
</form>
HTML3
}
#cut out from here
}
[download]

2006-06-13 Retitled by planetscape, as per Monastery guidelines

( keep:0 edit:7 reap:0 )

Original title: 'Interpolation'

Comment on Interpolation in a hash key Download Code

Replies are listed 'Best First'.
Re: Interpolation in a hash key by davorg (Chancellor) on Jun 13, 2006 at 15:51 UTC
Do you mean something like this: `$count+=1; if ($$hashRecordPtr{"price_product$count"} ne "" ) { print "<tr bgcolor=\"#EDEFF5\">"; if ($$hashRecordPtr{"connection${count}_description!} ne "") { print<<"CONNECTION1"; <td valign="middle" align="center" width="78">$$hashRecordPtr{"connect +ion${count}_size${count}"}</td> CONNECTION1 } # etc... }` [download] Note that in some cases I've had to use `${varname}` rather than `$varname` in order to disambiguate the variable name from the rest of the string. For future reference, it's helpful if you create a short extract of code which demonstrates your problem. And if you clean your code (add indentation - stuff like that) so that it's easy to read. -- <http://dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re: Interpolation in a hash key by ptum (Priest) on Jun 13, 2006 at 15:53 UTC
So, every place you have a '1' in a hash key, simply substitute this (untested): `${count}` [download] For example: `print<<"CONNECTION1"; <td valign="middle" align="center" width="78">$$hashRecordPtr{'connect +ion1_size1'} </td> CONNECTION1` [download] ... becomes ... `print<<"CONNECTION1"; <td valign="middle" align="center" width="78">$$hashRecordPtr{'connect +ion${count}_size${count}'} </td> CONNECTION1` [download] That should do it, no? At a glance, it looks like all your $$hashRecordPtr references are inside double-quoted strings or HERE docs ... No good deed goes unpunished. -- (attributed to) Oscar Wilde	[reply] [d/l] [select]
Re^2: Interpolation in a hash key by pickledegg (Novice) on Jun 13, 2006 at 16:26 UTC
Right, the bits in HERE docs, work fine as shown: `print<<"CONNECTION2"; <td width="78" align="center" valign="middle">$$hashRecordPtr{"connect +ion2_size$count"}</td> CONNECTION2` [download] But its just these bits now:(just a standard double quoted print statement) `print "<td width=\"78\" align=\"center\" valign=\"middle\">$$hashRecordPtr{'part_number1'}</td>";` Any ideas on this last bit? Nearly there, thanks guys.	[reply] [d/l] [select]
Re^3: Interpolation in a hash key by ptum (Priest) on Jun 13, 2006 at 16:34 UTC
So, in this last case, you've got a double-quoted string with a single-quoted substring. Interpolation rules indicate that a variable name inside the overall double-quoted string will still be resolved, so this should work (although it makes me nervous with all those backslashed double-quote characters): `print "<td width=\"78\" align=\"center\" valign=\"middle\">$$hashRecor +dPtr{'part_number${count}'}</td>";` [download] Of course, I could be wrong -- you should try it out. :) When in doubt, I use the curly braces, because I think it makes it more readable and it has saved my bacon once or twice. No good deed goes unpunished. -- (attributed to) Oscar Wilde	[reply] [d/l]
Re^4: Interpolation in a hash key by pickledegg (Novice) on Jun 14, 2006 at 08:07 UTC
Re^5: Interpolation in a hash key by davorg (Chancellor) on Jun 14, 2006 at 08:42 UTC
Some notes below your chosen depth have not been shown here
Re: Interpolation in a hash key by philcrow (Priest) on Jun 13, 2006 at 15:40 UTC
I don't think $$hashvar{key} interpolates correctly as a dereferencer inside double quotes. Try: `$hashRecordPtr->{'product_id'}` [download] etc. Phil	[reply] [d/l]
Re^2: Interpolation in a hash key by davorg (Chancellor) on Jun 13, 2006 at 15:43 UTC
I don't think $$hashvar{key} interpolates correctly as a dereferencer inside double quotes Seems to work fine here. What happened when you tried it? `$ perl -le '$h = {one=>1}; print "$$h{one}"' 1` [download] -- <http://dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re^3: Interpolation in a hash key by pickledegg (Novice) on Jun 13, 2006 at 15:58 UTC
Sorry chaps, I don't follow what you are doing there at all. I'm quite a novice. If I have: `$$hashRecordPtr{'connection1_size1'}` if I set $count to 3 how can I replace the size1 for size$count and get $$hashRecordPtr{'connection1_size3'} ? Do you see what I'm getting at? I know you do as you are way above me in the perl stakes, I just don't understand your answer, sorry.	[reply] [d/l]
Re^4: Interpolation in a hash key by davorg (Chancellor) on Jun 13, 2006 at 16:06 UTC
Re^5: Interpolation in a hash key by ptum (Priest) on Jun 13, 2006 at 16:18 UTC