If you have key => value pairs then a hash is the way to go:

my %hash;
# get data as hash
open FILE, $file or die $!\n;
while (<FILE>) {
    my ($key, $value) = split;
    $hash{$key} = $value;
}
close FILE;

my %changes = ( 'str1' => 'val1', 'str2' => 'val2' );

# change data in hash (or add new elements)
$hash{$_} = $changes{$_} for keys %changes

# overwrite old file with modified hash
open FILE, ">$file" or die $!;
print FILE "$_\t$hash{$_}\n" for keys %hash;
close FILE;
[download]

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

Hi!

Nice code - especially:

$hash{$_} = $changes{$_} for keys %changes

Greetz, Tom.

If assigning changes in a hash I prefer to do the following

@hash{keys %changes} = values %changes;
[download]

I believe it does the same thing (unless I'm missing something) as values() returns the hash values in the same order as keys().
TIMTOWTDI

broquaint

In that case, a hash is an ideal solution (assuming your file is not too big as to cause memory problems for you). once you have the hash populated, getting a value is as easy as:

  my $value_n = $hash{$str_n};
[download]

/prakash

my @list = qw(value1 value2);
unless (open (FILE, $filename)){
  die("Error in opening $filename: $!\n");
} # if

else {
  while (<FILE>){
    chomp($_);
    # split up to maximal "two columns" by whitespaces
    my ($str, $val) = split(/\s+/, $_, 2);

    # search @list for $val
    if ( grep { $val eq $_ } @list ){
      print "$val found\n";
    }
  } # while
  close (FILE);
} # else
[download]

  ...
  while (<FILE>){
    chomp($_);
    # split up to maximal "two columns" by whitespaces
    my ($val) = ( split(/\s+/, $_, 2) )[1];

    # search @list for $val
    if ( grep { $val eq $_ } @list ){
      print "$val found\n";
    }
  } # while

} # else
[download]

I haven't tested these codes.

Best regards,
perl -le "s==*F=e=>y~\*martinF~stronat~=>s~[^\w]~~g=>chop,print"

If you find yourself doing a grep inside a loop you essentially have an inefficient solution as you have one loop inside another (n*n) Paying the one off price to genreate a hash lookup table (or better still storing your data in this form) makes for far greater efficiency. An alternative in some instances is to build and compile a matching regex (outside the loop!) and use this in place of the grep/inner loop.

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print