Search Pattern And Arrays

[mercuryshipz]

#!/usr/bin/perl

#use strict;
use warnings;

  sub search_pattern
      {

          my $file_name = $_[0];

          my $search = $_[1];

          open(LOGFILE, $_[0]) or die("Error: cannot open file '$_[0]'\n");

          while (<LOGFILE>)
                {


if ( $_ =~ /$search/ ) {

my $val = $`;  #Matches Everything after pattern

$val =~ s/^\s+//; #remove leading spaces
$val =~ s/\s+$//; #remove trailing spaces
$val =~ s/\D//g;  #Just has the digits. All other charcters are filtered.

#print "$val\n";
print "\nFirst Occurence:$val \n";

my $line = $.;
print "Line number:$line\n";

#$temp = $line;
#print "$temp";
#print "$.";

last;
}
}
}

my $file_n ="test.txt";

my $search_p = "This is phrase 2";
&search_pattern($file_n, $search_p);

OUTPUT
------

First Occurence:90
Line number:3

Hi guys,

My code above searches for the first occurence of a phrase and returns the line number...

What if i wanna search for multiple search phrases in a single file and return the line numbers.

For example:
test.txt

1.This is phrase 1
2.This is phrase 3
3.This is phrase 2
4.This is phrase 3

any text in between

5.This is phrase 5

any text in between

6.This is phrase 4
7.This is phrase 1
8.This is phrase 2

9.This is phrase 3
10.This is phrase 6
11.This is phrase 7
12.This is phrase 1
13.This is phrase 2
14.This is phrase 3
15.This is phrase 4
16.This is phrase 8
17.This is phrase 1

.................
.................

i have given the line numbers for my reference in reality, it is not present...

The arguments passed are file_name and Search phrases (for eg: this is phrase1, this is phrase 2, This Phrase 3, phrase 5...)

The number of arguments passed may vary... But the first argument is always the file_name.

first it will check for phrase 1 and then from that line number phrase 2 (even though in our case Phrase 3 come in between phrase 2 ie., line 2 we need phrase 2 first and then phrase 3) and then phrase 3 and return phrase 3.

lets say we have 4 arguments including file name...

if (phrase 1 exists) ---------- if (phrase 1 doesnt exists)

from that line number ----------- search for phrase 2

search for phrase 2 ---------- if (phrase 2 also doesnt exists)

from that line number ---------- search for phrase 2 and return phrase 3

---------if (phrase 3 also doesnt exists)

----------- return phrase 2

----------- else phrase 1

search for phrase 3 ----------- if none of them exists display a message

return the phrase 3


the reason iam keeping track of line number is so that the file is not parsed from line 1.

if i know the number of arguments passed then its fine...

But the thing is what if i dont know the number of arguments presents.

can anybody suggest how do i proceed for this problem.

[Cabhan]

This is very easy. The arguments to a subroutine are stored in @_. You know that the first element of this array is the filename, so we could use code like the following:

sub mysub
{
    $filename = shift;
    $num_of_phrases = @_;
    ...
}

"shift" returns the first element of the given list (@_ by default) and removes it from the list. And when a list is evaluated in scalar context, it returns the length of the list.

Another approach that doesn't require you to know the number of arguments would be to shift off the first phrase, when you find it, shift off the second phrase, when you find it, shift off the third, etc. When @_ is finally empty, you will have gone through all of the phrases.