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Re: Re: Search and Replace

by Not_a_Number (Prior)
on Aug 27, 2003 at 20:37 UTC ( [id://287162]=note: print w/replies, xml ) Need Help??


in reply to Re: Search and Replace
in thread Search and Replace

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++; }

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++; }

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'; }

<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'; }

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'; }

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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