Beefy Boxes and Bandwidth Generously Provided by pair Networks
Don't ask to ask, just ask
 
PerlMonks  

Re: comparing two sets of data

by ColonelPanic (Friar)
on Nov 28, 2012 at 09:20 UTC ( #1005987=note: print w/ replies, xml ) Need Help??


in reply to comparing two sets of data

It appears that the "key" is the entire line of file1. If so, then this is a pretty easy task.

Here is an example:

use Modern::Perl; my %keys; open my $file1, '<', 'filename1.txt' or die "Can't open file 1: $!"; open my $file2, '<', 'filename2.txt' or die "Can't open file 2: $!"; #read in the first file. while (<$file1>) { chomp; #remove newline. $keys{$_}++; #Add the key to your hash } #find keys in the second file. while (<$file2>) { foreach my $key (keys %keys) { say "$key matches" if /\b\Q$key\E\b/; } }

Regex Notes: \b matches a word boundary. This is because you presumably wouldn't want "John Smith" to match "John Smithfield". \Q...\E is the quote literal modifier. If your key contains characters with a special meaning in regexes (such as the dot in "Mr. Smith") you want to match only the literal characters.

Yes, you do end up needing a nested loop...that is intrinsic to the nature of your task.



When's the last time you used duct tape on a duct? --Larry Wall


Comment on Re: comparing two sets of data
Select or Download Code

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1005987]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others having an uproarious good time at the Monastery: (10)
As of 2015-07-29 23:30 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









    Results (269 votes), past polls