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

i am trying to write a code to find two pattern from one file sequentially. while the code is running but only i am getting one pattern and not the second pattern. when i have added a print statement in second loop it shows n time "into the second loop.." print for the same no of times as n as no of lines in the file but not the second pattern 

opendir( my $synthdir,$target_dirsynth1) or die "Couldn't enter config
+ directory: $!\n";
          print("\nSYNTHESIS INPUT FILES IN CURRENT DIRECTORY \n");
          my $synthfilelist = glob "*.qsf";
          print ("\n$synthfilelist \n");

       my $originalquartus ;
       my $latestquartus ;
       my $readlineqo;
       my $readlineql ;

open (my $OFILE,$synthfilelist) || die "couldnt open file: $!";  
   while ($readlineqo = <$OFILE>) {
       chomp $readlineqo;
       if ($readlineqo =~ /ORIGINAL_QUARTUS_VERSION/) { 
       my @originalqarray = (split / +/ , $readlineqo);
       $originalquartus = $originalqarray[3];
       print "\nthe original quartus $originalquartus\n";
         }
     next if $readlineqo =~ /^ $/;
       }
   close($OFILE); 

open (my $LFILE,$synthfilelist) || die "couldnt open file: $!";  
   while ($readlineql = <$LFILE>) {
       chomp $readlineql;
       print "into the second loop $readlineql\n";
       if ($readlineql =~ /LAST_QUARTUS_VERSION/) { 
       my @latestqarray = (split / +/ , $readlineql);
       $latestquartus = $latestqarray[3];
       print "\nthe latest quartus $latestquartus\n";
       }
     next if $readlineql =~ /^ $/;
      }       
   close($LFILE);

[download]

Replies are listed 'Best First'.
Re: searching two pattern sequentially from one file
by haukex (Archbishop) on May 13, 2016 at 09:45 UTC

    Hi mrityunjaynath,

    When I create a simple test input file

    ORIGINAL_QUARTUS_VERSION a b c d
LAST_QUARTUS_VERSION w x y z

    [download]

    Your code works for me (after commenting out the initial opendir, which appears unnecessary), giving the (I assume) expected output "the original quartus c" and "the latest quartus y".

    Are you sure your input file contains the string "LAST_QUARTUS_VERSION"? Could you show a sample input file for which your code fails? See Short, Self Contained, Correct Example.

    Note that you don't need to open the file twice, you can combine your two loops into one:

    my $originalquartus;
my $latestquartus;
open( my $OFILE, $synthfilelist ) || die "couldnt open file: $!";
while ( my $readlineqo = <$OFILE> ) {
    chomp $readlineqo;
    if ( $readlineqo =~ /ORIGINAL_QUARTUS_VERSION/ ) {
        my @originalqarray = ( split / +/, $readlineqo );
        $originalquartus = $originalqarray[3];
        print "\nthe original quartus $originalquartus\n";
    }
    if ( $readlineqo =~ /LAST_QUARTUS_VERSION/ ) {
        my @latestqarray = ( split / +/, $readlineqo );
        $latestquartus = $latestqarray[3];
        print "\nthe latest quartus $latestquartus\n";
    }
    next if $readlineqo =~ /^ $/;
}
close($OFILE);

    [download]

    Also, you use glob in scalar context, which only returns one file at a time, but you call the results variable $synthfilelist and you output it as "input files in current directory" - this might lead to some confusion as it will only ever be one file per glob call.

    Small update: Using a next statement as the very last thing in a loop is not necessary as the loop will go to the next iteration anyway, so unless you have code following it you can remove that line.

    Hope this helps,
    -- Hauke D

[reply]
[d/l]
[select]

      thanks Haukex.. this a part of long code so opendir is needed . for next statement i will comment it as u are right it seems unnecessary. the code is working fine but i i am not getting last quartus version value rather i am getting a infinite loop of into the second loop along with $readlineql value. following is the snippet from input file bifrost.qsf

      set_global_assignment -name FAMILY "Cyclone III"
      set_global_assignment -name DEVICE EP3C40F484C7
      set_global_assignment -name TOP_LEVEL_ENTITY Emap8S
      set_global_assignment -name ORIGINAL_QUARTUS_VERSION 9.1
      set_global_assignment -name PROJECT_CREATION_TIME_DATE "13:05:54 JUNE 27, 2011"
      set_global_assignment -name LAST_QUARTUS_VERSION 11.1
      set_global_assignment -name USE_GENERATED_PHYSICAL_CONSTRAINTS OFF -section_id

[reply]

        Hi mrityunjaynath,

        When I run your code against this sample input, I get the output "the original quartus 9.1" and "the latest quartus 11.1" - so it would seem that the problem is happening elsewhere in your code.

        To narrow down where the problem is occurring, sometimes the simplest thing to do is print debug output at strategic places in your code to monitor its progress, see also the Basic debugging checklist. Another option is stepping through your code with the debugger (tutorial).

        Once you've narrowed down where your problem is occurring, boil down your code and sample input into a Short, Self Contained, Correct Example, that is, a piece of code that compiles and reproduces the problem, along with its sample input and the expected output vs. actual output including error messages (see also How do I post a question effectively?), and post it here.

        Often this process will help you discover the bug and the fix too! :-)

        Hope this helps,
        -- Hauke D

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