Re: Match a string only once in a file

Here is another way that reads one line at a time and stops early when all strings are found:

# The first part is the same as the original.

open IN, $Filename or die "Could not open file $!";
 
@array = ('file', 'this', 'dog', 'forward');
my %guard;
 
READLOOP:
while (<IN>)
  {
   foreach $searchstring (@array)
     {
     if (m/$searchstring/i)
      {
       if (! exists $guard{$searchstring}) {
          push @stringsfound, $searchstring;
          last READLOOP if @stringsfound == @array;
          $guard{$searchstring} = 1;
       }
      }
    }
  }
 
close IN;

# a somewhat nicer output
print join(" ",@stringsfound),"\n";
[download]

Comment on Re: Match a string only once in a file Download Code

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Re^2: Match a string only once in a file by Roy Johnson (Monsignor) on Mar 08, 2005 at 01:10 UTC
It tidies up nicely and does less searching if you modify the foreach loop: `foreach $searchstring (grep {!exists $guard{$_}} @array) { if (m/$searchstring/i) { push @stringsfound, $searchstring; $guard{$searchstring} = undef; } }` [download] Caution: Contents may have been coded under pressure.	[reply] [d/l]