Re: Search and Replace

Thank you all for your precious help once again.

I´ve made the following code that works

use strict;
use warnings;

my $path='D:\npodev\forms\src';
my @intervalos= ("[a-e]", "[f-h]", "[i-m]", "[n]", "[o-s]", "[t-z]");
my $esquema="RMS_MC";
my $start_flag = '<REANALYZED>';
my $stop_flag = '</REANALYZED>';

sub procura_ficheiros{
  my ($path,$intervalo)=@_;
  opendir(DIR, $path) ||die "$!";
  my @files=grep{/^$intervalo.*\.[f|m]/i} readdir(DIR);
  closedir (DIR);
  my $aux=0;
  foreach my $pos (@files){
    $files[$aux]="\t\"".$path."\\".$files[$aux]."\""."   $esquema\n";
    $aux++;
  }
return @files;
}

foreach my $intervalo (@intervalos){
    my @ola=procura_ficheiros($path,$intervalo);
    my $replacement = join "", @ola;
    open ORIGINAL, "< teste.txt"
    or die "can't open original file\n";
    my $original;
    {
      local $/;
      $original = <ORIGINAL>;
    }
    close ORIGINAL;

    $original =~ s/
        $start_flag
        .*?
        (\s*)
        $stop_flag
        \n
        /$start_flag\n$replacement$1$stop_flag/gsx;

    open COPY, "> copy.txt"
    or die "can't write to copy\n";
    print COPY $original;
    close COPY;
    system "hello.bat";
}
[download]

Thank you..

Nuno

Comment on Re: Search and Replace Download Code

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Re: Re: Search and Replace
by Not_a_Number (Prior) on Aug 27, 2003 at 20:37 UTC

If it ain't broke, there's no need to fix it. Right. Nevertheless, these lines jumped out at me:

my $aux=0;
foreach my $pos (@files){
  $files[$aux]="\t\"".$path."\\".$files[$aux]."\""."   $esquema\n";
  $aux++;
}
[download]

1. Variable interpolation

First, take the line:

$files[$aux]="\t\"".$path."\\".$files[$aux]."\""." $esquema\n";

This reminds me of something else I saw recently, which (simplified) read something like this:

my $line = $first . " " . $second . " ". $third;

As if Perl didn't allow variable interpolation! Your line can be simplified to:

$files[$aux]="\t\"$path\\$files[$aux]\" $esquema\n";

Further, by using qq(), you would no longer have to escape the double quotes:

$files[$aux] = qq '\t"$path\\$files[$aux]" $esquema\n';

which I for one find a bit easier on the eye.

2. for/foreach loops

But now to come to your foreach loop (inner bit modified as above):

my $aux=0;
foreach my $pos (@files){
  $files[$aux] = qq '\t"$path\\$files[$aux]"   $esquema\n';
  $aux++;
}
[download]

I'm far from being a Perl guru, but I think I may safely say that this is ugly :) You can do this far more efficiently in Perl:

foreach my $pos ( 0 .. $#files ) {
  $files[$pos] = qq '\t"$path\\$files[$pos]"   $esquema\n';
}
[download]

<parenthesis>Occasionally, you might also come across some rather quaint variations of the above, along the lines of:

foreach ( my $pos = 0; $pos < @files; $pos++ ) { ... }

but it's best to forget these unless you want to increment your counter ($pos) by anything other than 1.</parenthesis>

However, you would still not be using the full power of Perl. To quote Marc Jason Dominus: "Any time you have a C-like for loop that loops over the indices of an array, you're probably making a mistake." A more perlish way to do what you want would be:

foreach my $file ( @files ) {
   $file = qq '\t"$path\\$file"   $esquema\n';
}
[download]

In fact, you can use Perl's built-in $_ variable to shorten that even further:

for ( @files ) {    # 'for' and 'foreach' are equivalent
   $_ = qq '\t"$path\\$_"   $esquema\n';
}
[download]

From which, to end this far longer than intially intended post, it is only a short step to using map:

@files = map { qq '\t"$path\\$_" $esquema\n' } @files;

HTH

dave

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