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RE: RE: Re: Search Algorithm

by tenfourty (Novice)
on Aug 10, 2000 at 21:36 UTC ( #27339=note: print w/replies, xml ) Need Help??

in reply to RE: Re: Search Algorithm
in thread Search Algorithm

Firstly thanks for all your responses and for the help that you guys have given me.

I slept on what you gave me and I realised that the perl only searches for single keywords, however my keywords are sometimes several words long.

Just to let you know what my program does, it searches for non-ansi sql within source code. so the config file for my program is a list of oracle specific sql to search for. an example of a keyword is ALTER TABLE etc. I need to find all occurences of this in a file. the other thing that the code has to do is highlight multiple occurences of keywords in the same line

this is why the code you gave me doesn't work as it goes through and searches word by word for each line

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RE: RE: RE: Re: Search Algorithm
by mikfire (Deacon) on Aug 10, 2000 at 22:28 UTC
    # while not EOF keep going while ( <DATA> ) { $lineCount++; # increment the lineCount for my $word ( @words ) { my $pat = $regex{ lc($word) }; #next word unless the word is a keyword so store a report in @ +found next unless ( /$pat/ ); @found = (@found, "\nError in line $lineCount of file $file oc +curence of \"$word\" :\n\t@words\n"); $foundCount++; # increment total found words } }
    First, lets make this a bit less painful. Sorry this is not directly answering your problems, I will get to that in a bit.

    First and foremost, You need to stop that @found assignment. It is really painful to look at. The perlish way ( highly optimized as well as reading better ) is to push like

    push @found, "\nError in line $lineCount of file $file occurence of \" +$word\" :\n\t@words\n";
    The way you do that previously causes perl to expand the array to a list and then puts it back into the array. That expansion step is going to get very costly. The push doesn't bother with all that, it just tacks the data onto the end of the array.

    You can also get rid of the lineCount variable if you wish. Perl automagically keeps track of the current line number and stores that in $.

    Now, onto you problem. I am worried about this line

    # read in all the keywords from the configFile and put all the words i +nto a hash %regex = map { $_ => qr/$_/ } init_keywords ($ConfigFile); # init_keywords just returns an array of keywords all in lower case. ....
    this means you will only match words when they are in lower case. Without knowing your data set, I cannot say for certain if this is your problem, but that is my guess. You can solve this many ways, but frankly I think something like
    %regex = map { $_ => qr/$_/i } init_keywords ($ConfigFile);
    is the cleanest way to do it. The additional /i modifier tells the regex to ignore case when doing the match.

    Beyond this, you will need either somebody better than I am at this stuff ( and there are plenty of them here ) or I will need a sample of your data - both the key words and the files you are parsing.


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