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

Hi! I have the following cgi script: 
#!/agl/tools/perl/bin/perl
my @a=qx (rsh -l sonaxisz 'source.login ; findbug -p | sort -u | %s se
+rver);
print "Content-type:text/html\n\n";
print "<html><body>";
print "<table>";
print "<tr><td>@a<td><tr>";
print "</table></body></html>";

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in the @a array i want to put the values that come from the command. The problem is that i want to print each value from the array in a separate table cell but i can't! in this way @a looks like this @a=ABC and puts ABC in the same cell and i want to put A in a cell, B in other cel, and C in other cel! I've tried with $a[0], $a[1], $a[2] but it also writes ABC at each!
Can you help me? Thank you very much!

Janitored by ybiC: Replace literal [ and ] with &#091; and &$093; to avoid PM-linking.

Replies are listed 'Best First'.
Re: array problem
by katgirl (Hermit) on Sep 12, 2003 at 12:55 UTC
    @a = ABC isn't an array. Do you mean @a = ("A","B","C");? If so... 

    #!/agl/tools/perl/bin/perl
my @a=qx (rsh -l sonaxisz 'source.login ; findbug -p | sort -u | %s se
+rver);
print "Content-type:text/html\n\n";
print "<html><body><table>";
for(@a){
print "<tr><td>$_</td></tr>";
}
print "</table></body></html>";

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    the for loop takes each item in the list @a and applies the code within the loop - but you could use map instead: 
    @a = ("A","B","C");
print "Content-type:text/html\n\n";
print "<html><body><table>";
print map("<tr><td>$_</td></tr>",@a);
print "</table></body></html>";

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    any good for you?
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      It is a very good ideea but i am not sure if qx returns separate items for output! I relly don't think so! Do you know any quotelike operators that returns separate items for output! Thank you for your time!!
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    		[reply]

          Wait...qx will return a list of command output lines...if your pipeline outputs newline separated lines, then you'll get a list of the kind that you seem to want.

          Compare this code and its outputs with what you have done. 

          my @a = map {s/\n//g ? $_ : ()} `netstat -an`;
print "$_\n" for @a;

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    Re: array problem
    by Abigail-II (Bishop) on Sep 12, 2003 at 12:57 UTC 
      my @a=qx (rsh -l sonaxisz 'source.login ; findbug -p | sort -u | %s se
+rver);

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      Are you sure this works? I only see one quote.

      Having said that, the amount of elements you get in @a depends on the number of lines your command returns. Each line becomes a separate element. However, if you do 

      print "<tr><td>@a<td><tr>";

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      then you will get a single HTML table cell, no matter how many elements you have in your array - unless of course the array (or $") contains "<td>".

      Abigail

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    Re: array problem
    by bart (Canon) on Sep 12, 2003 at 12:39 UTC
      First off: are you sure the qx() operator returns separate items for output?

      You haven't inserted anything between the array items (except the default spaces). You're supposed to insert "</td><td>" between the cells. The easiest way to get that effect is 

      local $" = "</td><td>";

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      p.s. You should fix your tags, you don't have closing "<td>" and "<tr>" tags, but opening tags instead. And you might reconsider escaping the special HTML characters in your data, especially "<" and "&".

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        i typed wrong, i have closing operators but i am not sure if qx returns separate items for output! I relly don't think so! Do you know any quotelike operators that returns separate items for output! Thank you for your time!!
    		[reply]
          Check out perlop, where it says about qx() (or backticks, ``, which most of us will be more familiar with):
          In list context, returns a list of lines (however you've defined lines with $/ or $INPUT_RECORD_SEPARATOR), or an empty list if the command failed.
          By default, that is a newline. So the list returned contains one item per line. The question remains: does your command line return a multiline result? I'm not familiar with what you try to do, so I can't tell.

          You can easily test in two ways: 

          • @a = qx(COMMANDLINE);
print scalar @a;

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          • $a = qx(COMMANDLINE);
print "<plaintext>$a";

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          The former will print the number of items, the latter will make the browser display the text as plaintext, line wrapping an all.

          I just hope that yo ucan tweak your command line so that you can get separate lines for the returned items. If not, you can set $/ to whatever string separates the data items.

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    Re: array problem
    by Roger (Parson) on Sep 12, 2003 at 13:27 UTC
      Hi, why don't you try something like:
      my $return_value = `rsh ...`; # your command
my @a = split /\s+/, $return_value;
print "Content-type: text/html\n\n<html><body><table>\n";
foreach (@a) { print "<tr><td>$_</td></tr>\n" }
print "</table></body></html>\n";

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      Assuming that your rsh command returns a set of values separated by spaces. Change the split pattern if the output of the rsh uses a different separator.
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    Re: array problem
    by TomDLux (Vicar) on Sep 13, 2003 at 16:31 UTC

      You seem totally confident concerning the value of @a, without presenting any reasons or evidence. How about running a little test script:

      #!/agl/tools/perl/bin/perl
use strict;               # Notice these two 
use warnings;             # essential modifications!
my @a=qx (rsh -l sonaxisz 'source.login ; findbug -p | sort -u | %s se
+rver');
print '@a contains ' . scalar @a . "elements:\n", @a;\

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      Betcha a mug of Trappist Ale you'll be surprised at the output.

      --
      TTTATCGGTCGTTATATAGATGTTTGCA

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