Since you provided some code (although not Perl code), I am willing to bring you a bit further: 
while (my $line = <$file>) {
    chomp $line; # remove trailing end of line character
    my @F = split /,/, $line;
    for my $i (1..3) {
        if ($F[0]+ $i == $F[1] and $F[1]+$i == $F[2]) {
            warn "row $.: $_\n";
        } else {
            print $line, "\n";
        }
    }
}

[download]
Not sure though that this implements the logic that you want. Your Python program does not do the same thing as the Perl one-liner, so I don't really know what you want. If you want to test for each value in the (1..3) range and print if none of the conditions matched then it should rather something like this: 
LINE: while (my $line = <$file>) {
    chomp $line;
    my @F = split /,/, $line;
    for my $i (1..3) {
        if ($F[0]+ $i == $F[1] and $F[1]+$i == $F[2]) {
            warn "row $.: $_\n";
            next LINE; # the condition matched, go immediately to the 
+next input line, do not print
        }
    }
    print $line, "\n";
}

[download]

In reply to Re: Searching for Patterns in CSV by Laurent_R
in thread Searching for Patterns in CSV by Fischer

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