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Re^3: How to check lines that start with the same word then delete one of them

by hippo (Chancellor)
on Apr 10, 2020 at 12:38 UTC ( #11115313=note: print w/replies, xml ) Need Help??


in reply to Re^2: How to check lines that start with the same word then delete one of them
in thread How to check lines that start with the same word then delete one of them

use strict; use warnings; use Test::More tests => 1; my @in = ( 'S_FER_SCAM1_ARRESTO;ARRESTO;ST;0;ST;1;0;TS;0;0', 'S_FER_SCAM1_ARRESTO;ARRESTO;SU LI IR ST;0;SU LI IR ST;1;0;TS;0;0' ); my @want = ( 'S_FER_SCAM1_ARRESTO;ARRESTO;ST;0;ST;1;0;TS;0;0', ); my @have; my %seen; for (@in) { /^(\w+)/; if (exists $seen{$1}) { next if (/SU LI IR ST/); # More code here if it doesn't match - this section not descri +bed. } $seen{$1} //= $_; push @have, $_; } is_deeply \@have, \@want, 'Arrays match';

See also How to ask better questions using Test::More and sample data.

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Re^4: How to check lines that start with the same word then delete one of them
by LanX (Archbishop) on Apr 10, 2020 at 13:26 UTC
    Pretty much what I meant, thanks!

    Minor nitpick, I'd assign the first match to a normal var.

    Special vars like $1 can get overwritten easily by "more code" before seen is set.

    Cheers Rolf
    (addicted to the Perl Programming Language :)
    Wikisyntax for the Monastery

      Cool - glad we're in agreement.

      You are quite right about limiting the chances of stomping on $1 and friends, of course. The test script could be polished no doubt but I didn't want to spend/waste time on that before agnes00 confirmed that this does actually solve the problem. The requirements as stated were a little wooly.

        > I didn't want to spend/waste time on that ... The requirements as stated were a little wooly.

        That's why I thanked you for implementing it. :)

        Cheers Rolf
        (addicted to the Perl Programming Language :)
        Wikisyntax for the Monastery

Re^4: How to check lines that start with the same word then delete one of them
by agnes00 (Novice) on Apr 10, 2020 at 13:01 UTC
    Thank you for your answer. The problem is that I've a big file (40000 line), that's why I did'nt bring it to my post. and also I can't specify all the wanted lines, I just want to check if for every line there is another line witch have the same first word then I check it to delete one of them, that's why I did two loops. but the algorithm is so slow
      The problem is that I've a big file (40000 line), that's why I did'nt bring it to my post.

      Everyone is glad you didn't. "Sample data" means just that. Pick maybe 6 lines - enough to be illustrative and to cover the bases. My script above is a test only. It illustrates that the algorithm and the code works, given the sample data.

      I just want to check if for every line there is another line witch have the same first word then I check it to delete one of them,

      This is precisely what my test shows. Would you not agree? To turn the test into a working script just replace @in with the code you already have which reads the input data from the file and similarly write @have to your file at the end.

      that's why I did two loops. but the algorithm is so slow

      Your algorithm is O(n2) whereas mine is O(n). Mine should therefore be thousands of times faster for a 40,000 line dataset.

      See also: Big O notation, SSCCE and Basic Testing Tutorial. HTH.

        I think your solution works in O(n*log n), because searching an item in a hash takes log n. Am I right? Still much much faster that O(n*n) :)
Re^4: How to check lines that start with the same word then delete one of them
by agnes00 (Novice) on Apr 10, 2020 at 16:56 UTC
    I've tested your code with this input :
    my @in = ( 'S_FER_SCAM1_ARRESTO;ARRESTO;ST;0;ST;1;0;TS;0;0', 'S_VINREU_RLIP1_ALLARMEZONA3;ALLARME ZONA 3;SU LI IR ST;0;SU LI I +R ST;1;0;TS;0;0', 'S_VINREU_RLIP1_ANOMBAT;ANOMALIA BATTERIA;SU LI IR ST;0;SU LI IR S +T;1;0;TS;0;0', 'S_FER_VENT1_ERRCOLINV;ERRORE PROFIBUS COLL INVERTER;SU LI IR ST;0 +;SU LI IR ST;1;0;TS;0;0', 'S_VINREU_RLIP1_CIRCZONE1;CIRCUITO ZONA 1 FUNZONANTE;SU LI IR ST;0 +;SU LI IR ST;1;0;TS;0;0', 'S_VINREU_RLIP1_CIRCZONE2;CIRCUITO ZONA 2 FUNZONANTE;SU LI IR ST;0 +;SU LI IR ST;1;0;TS;0;0', 'S_FER_SCAM1_ARRESTO;ARRESTO;SU LI IR ST;0;SU LI IR ST;1;0;TS; +0;0', 'S_FER_VENT1_ERRCOLINV;ERRORE PROFIBUS COLL INVERTER;ST;0;ST;1;0;T +S;0;0' );
    I print  @have array and it shows 7 lines with  S_FER_VENT1_ERRCOLINV is duplicated (should show only 6), it hide only one, in my data file I've lines that have the same id ($1) two times and others are normal (no duplicate id)

      That's because you have changed the criteria. 'S_FER_VENT1_ERRCOLINV;ERRORE PROFIBUS COLL INVERTER;ST;0;ST;1;0;TS;0;0' does not match the check in your initial post of

      if($var eq $1 and $line2 =~ /(.*?);.*?;SU LI IR ST;.*?;SU LI IR ST;.*? +;.*?;.*?;.*?;.*?(?:$)/)

      ... so it has not been removed. Did you not mean this? Was your initial post misleading?

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