beginers help.... 4

[wh3e]

Hey.. I got a simple question !?!?!?
If I got a document I want to read.. it looks like this.

-pornchan
bla bla.
bla bla bla.
----------
-mychan
bla and bla.
bla bla blue.
----------

When I execute the perl script with "perl lame.pl mychan" then I want to print
bla and bla.
bla bla blue.

Thats my problem..
If many ways.. i want it to be fast.. pretty big file..
And one more question.....
Is there any way to check if "word" is in a line?
//wh3e

 

[KevinADC]

What have you tried? Do you know any perl?

------------------------------------------
- Kevin, perl coder unexceptional!

 

[stevexff]

Thats my problem..

Not quite. Your real problem is that you want someone to do it for you, for free.

But I don't want to come over completely negative here. In answer to your second question, you can use a regular expression to check if a word exists in a line

while (<>) {
   print if (/veeblefetzer/);
}

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[wh3e]

That part aint the whole program...
Thats the part I can't get to work..
I'm pretty none knowing when I gets to perl.
I can make it read the file.. But can't start and stop on diffrent lines... Thanx for the other info.

 

[stevexff]

use strict;
use warnings;

my $channel = shift;
my $start = qr{^-$channel$};

while (<>) {
   if (/$start/ .. /^-+$/) {
      print unless (/^-/);
   }
}

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[tchatzi]

a

http://wwww!!!

Stevexff you are a poet!!


``The wise man doesn't give the right answers,
he poses the right questions.''
TIMTOWTDI

 

[PinkeyNBrain]

Well done Stevexff. Question - would you be able to shave a clock cycle or two by removing the semicolon on the print statement? Save the parser from reading in that extra character on startup.

 

[stevexff]

Mmm. While we are shaving clock cycles, let's do it right:

print unless (substr($_, 0, 1) eq '-') [red]# ;[/red]

would probably be faster, over the course of several million iterations. Along with my own personal favourites, removing the strict and warning pragmas...

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[PinkeyNBrain]

FWIW - timed two loops over the suggested code above. After 1 million iterations, /^-/ averaged 0.65 secs and substr(xxx) averaged 0.33 seconds. (ok so it's a slow day today)

 

[KevinADC]

unpack is rumored to be faster than substr:

print unless unpack("A1",$_) eq '-';

Maybe someone can put that rumor to the test.


------------------------------------------
- Kevin, perl coder unexceptional!

 

[PinkeyNBrain]

Here is the code I used:

use Time::HiRes qw(gettimeofday);
$max = 10000000 ;
while ($max != 0) {
   $t0 = gettimeofday ;
   for ($i=0;$i<$max;++$i) {
      print unless (/^#/) ;
   };
   $test1 = gettimeofday - $t0;
   $t0 = gettimeofday ;
   for ($i=0;$i<$max;++$i) {
      print unless (substr($_, 0, 1) eq '#') ;
   };
   $test2 = gettimeofday - $t0;
   $t0 = gettimeofday ;
   for ($i=0;$i<$max;++$i) {
      print unless unpack("A1",$_) eq '#' ;
   };
   $test3 = gettimeofday - $t0;
   print "Test 1 >$test1<  Test 2 >$test2<  Test 3 >$test3<\n";
   print "(prev $max) Next max (0 exit) : ";
   $max = <STDIN> ; chomp $max ;
};

Results off a basic 2.8GHz Intel chip running perl5.10.0

Test 1 >6.39087104797363< Test 2 >3.46887302398682< Test 3 >11.312922000885<
(prev 10000000) Next max (0 exit) : 0

 

[PinkeyNBrain]

Sorry about the extra ;'s. Old habits.

 

[stevexff]

So much for that rumour, then. Star for PinkeyNBrain, for the effort.

I suspect that the OP is losing the will to live at this point, but I've learned more from this thread than I ever suspected I would when it started...

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]