Re: Re: comparing files

thanks for the help....basically if i have two files, and for every name that matches in the first column (not necessarily the same number of lines in the two files), i want to print out the second and third columns of the second file.....does code in the previous posting make sense? so i have file 1:

case1 23  home
case2 45  match
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and file 2:

case0 22 match
case5 55 home
case2 32 match
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so i want my file to print out

case2 32 match
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thanks for the all the help

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Re: Re: Re: comparing files by mephit (Scribe) on Aug 23, 2002 at 21:09 UTC
`perldoc -q contain` Found in /usr/lib/perl5/5.6.0/pod/perlfaq4.pod How can I tell whether a list or array contains a certain element? Hearing the word "in" is an indication that you probably should have used a hash, not a list or array, to store your data... Populate a hash with the keys as the values of the first column of the first datafile, then loop through the second file and check for the existence of the corresponding number in the hash, as such: (I used pattern matching 'cause that's the first thing that popped into my head, but you can use whatever's best for your particular datafile.) `my %h1; while (<ONE>) { $h1{$1} = $2 if /^(\d)+\s+(.+)/; } while (<TWO>) { /^(\d)+\s+(.+)/; printf "Match: %s\t%s\n", $1, $2 if exists $h1{$1};` [download] I don't know how efficient this is, but it works. HTH. -- There are 10 kinds of people -- those that understand binary, and those that don't.	[reply] [d/l] [select]

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Re: Re: Re: comparing files
by mephit (Scribe) on Aug 23, 2002 at 21:09 UTC

perldoc -q contain

Found in /usr/lib/perl5/5.6.0/pod/perlfaq4.pod How can I tell whether a list or array contains a certain element? Hearing the word "in" is an indication that you probably should have used a hash, not a list or array, to store your data...

my %h1;
while (<ONE>) {
  $h1{$1} = $2 if /^(\d)+\s+(.+)/;
}
while (<TWO>) {
  /^(\d)+\s+(.+)/;
  printf "Match: %s\t%s\n", $1, $2 if exists $h1{$1};
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There are 10 kinds of people -- those that understand binary, and those that don't.

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