Tan has asked for the wisdom of the Perl Monks concerning the following question:

Dear All,

Please find the script below which although doesnt have immediate errors..is not what I was hoping it would acheive!

#perl -w
print("Importing two data files \n");


# Lets open up file A which reads data from names_ticker to FILE_A
open(FILE_A, "< Names_Ticker.txt")
        or die "Couldn't open Names_Ticker for reading: $!\n";
@fileA=<FILE_A>;
close(FILE_A);
print "@fileA \n";

# Lets open up file B which reads data from names_offer to FILE_B
open(FILE_B, "< Names_Offer.txt")
        or die "Couldn't open Names_Offer for reading: $!\n";
@fileB=<FILE_B>;
close(FILE_B);

print "@fileB \n";





#Print the lists generated with commas... sort the format out!

#sub commify_series {
#        my $sepchar = grep(/,/ => @_) ? ";" : ",";
#        (@_ == 0) ? ''                   :
#        (@_ == 1) ? $_[0]                :
#        (@_ == 2) ? join(" and ", @_)    :
#                    join("$sepchar ", @_[0..($#_-1)], "and $_[-1]");
#                    }
#
#foreach $aref(@fileB) {
#        print "This lists contains: " . commify_series(@aref) . ".\n"
+;
#
#}


print("Comparing company names between two files\n");

# Essentially we want to find elements that are in one array but not a
+nother,
# that is find elements in @fileA that arent in @fileB.
# Solution? build hash keys of @fileB to use as a lookup table. Then c
+heck each
# element in @fileA to see if it is in @fileB

%seen = () ;             # lookup table to test memebership of @fileB
@aonly = () ;            # answer

# build lookup table
foreach $item (@fileB) { $seen{$item} = 1}

# find only elements in @fileA and not in @fileB
foreach $item (@fileA) {
        unless ($seen{$item}) {
        # its not in %seen, so add to @aonly
        push(@aonly, $item);
        }
}

print "@aonly \n";



print("Saving matched company records as new file\n");

[download]

Ideally, as suggested from previous email - I am merging two records @fileA and @fileB into a single new file which is given as @aonly.

Problems I face:
  1. the contents of @fileA and @fileB - I would like to convert everything into lower capitals
  2. can I add a search condition to this script which would search (a) the first 4 letters of each string in the arrays (either from the start or end of line? )

Your advice will be appreciated.

regards

Edited by Chady -- cleaned up formatting

Replies are listed 'Best First'.
Re: Fuzzy Matching
by !1 (Hermit) on Dec 30, 2003 at 09:55 UTC

    1. map and lc are your friends.

    2. I don't know what exactly you want but I can tell you substr will definitely help as might split.

    As a side note: you may wish to use code tags (<code></code>) next time you wish to post code.

[reply]
    A reply falls below the community's threshold of quality. You may see it by logging in.
Re: Fuzzy Matching
by Art_XIV (Hermit) on Dec 30, 2003 at 14:10 UTC

    I'm not sure what the question really is, but maybe this will give you some ideas:

    #Don't forget to use these!
use warnings;
use strict;

my %in_file_b;
my @aonly;
my ($file_a, $file_b) = ('Names_Ticker.txt', 'Names_Offer.txt');

print("Importing two data files \n");

#Look at FILE_B first since we will be eliminating elements 
#from FILE_A based upon its contents
open(FILE_B, "<$file_b")
        or die "Couldn't open $file_b for reading: $!\n";
while (<FILE_B>) {
    chomp;
    #the key will be the first four chars of the line, lowercase
    my $entry = lc( substr $_, 0, 4); #substr $_, -4 would get last fo
+ur
    $in_file_b{$entry} = 1;
}
close FILE_B;

open(FILE_A, "<$file_a")
        or die "Couldn't open $file_a for reading: $!\n";
while (<FILE_A>) {
    chomp;
    my $entry = lc( substr $_, 0, 4);
    #add the entire line if the value of $entry isn't in %in_file_b
    push @aonly, $_ unless exists $in_file_b{$entry};
}
close FILE_A;

print "@aonly\n";

1;

    [download]

    Processing it like this avoids slurping one of the files into memory.

    Hanlon's Razor - "Never attribute to malice that which can be adequately explained by stupidity"
[reply]
[d/l]

Back to Seekers of Perl Wisdom