It seems to me like you're over-thinking your algorithm. What you want to express in code is "for each line of data, if the value in the second column is contained in my pre-existing dataset (@all), print the line". Perl is very expressive, so it allows you to say that almost directly:
#!/usr/bin/env perl
use strict; use warnings;
@all = ("7723","7725","9908","7765","7874");
while( <DATA> ) {
my @column = split /\s+/; #get columns out of data line
for my $x (@all) {
next unless $x == $column[1]; # compare second column, move on i
+f no match
print $_; # we found a match, print out the original line
last; # we're done, so stop comparing this line
}
}
__DATA__
77876 8543 CA84985 54E
77873 8003 CA84985 54E
77875 7725 CA84985 54E
77872 8511 CA84985 54E
77873 8123 CA84985 54E
77822 9908 CA84985 54E
77819 8503 CA84985 54E
77826 8040 CA84985 54E
77822 7874 CA84985 54E
77884 8543 CA84985 54E
77809 7211 CA84985 54E
However, a knowledge of design patterns yields a more elegant solution suggested by the Schwartzian Transform.
#!/usr/bin/env perl
use strict; use warnings;
@all = ("7723","7725","9908","7765","7874");
# partial application of the Schwartzian Transform
# each unique value in @all will now be a key in the %all hash
my %all = map { $_ => 1 } @all;
while( <DATA> ) {
my @column = split /\s+/; #get columns out of data line
print $_ if $all{$column[1]};
}
__DATA__
77876 8543 CA84985 54E
77873 8003 CA84985 54E
77875 7725 CA84985 54E
77872 8511 CA84985 54E
77873 8123 CA84985 54E
77822 9908 CA84985 54E
77819 8503 CA84985 54E
77826 8040 CA84985 54E
77822 7874 CA84985 54E
77884 8543 CA84985 54E
77809 7211 CA84985 54E
The transformation of array to hash allows the check to be very simple: "does our dataset contain this value?".
<–radiant.matrix–>
Ramblings and references
The Code that can be seen is not the true Code
I haven't found a problem yet that can't be solved by a well-placed trebuchet
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