going to a particular Line Number in a File ??

[ryen]

I'm aware of PERL's seek function, but it only accepts the byte-position, correct? Is there any way to go to a particular line number in a file? That is, without making a custom function which reads each newline character, and keeps track of the line number, etc.

For instance, say I wanted to go to line 50,045.. i don't see any way it would could be built into perl, but it'd be nice if it was, any help would be greatly appreciated.
-Ryen

 

[NEVERSLEEP]

open(&quot;<$file&quot;,DATA) || die &quot;dead $!&quot;;
while (<DATA>) {
print &quot;\n$_[$wanted]&quot;;
}
close(DATA);

not sure about this last one u could also do :

open(&quot;<$file&quot;,DATA) || die &quot;dead $!&quot;;
@storer;
close(DATA);
print &quot;\n$storer[$wanted]&quot;; someone knowledge ends where
someone else knowledge starts

 

[ryen]

hmm... I think I see what you're going for, I'll experiment and see if I can figure anything out. Thanks a bunch for the input

 

[ryen]

ohhhh sorry i see what you're saying. well, i would do that, but then I'd have to read the whole file into an array... which would work, but not on a really huge file. I think my best bet is to try and do something with the seek command.. which might be hard to do if the database fields/records are varying in size.. and i don't know a lot about binary reading/writing... hmm.. thanks again tho.

 

[NEVERSLEEP]

open(&quot;<$file&quot;,DATA) || die &quot;dead $!&quot;;
while (<DATA>) {
print &quot;\n$_[$wanted]&quot;;
}
close(DATA);

is not working ? someone knowledge ends where
someone else knowledge starts

 

[NEVERSLEEP]

why didn't u say sooner that its was a binary file
read this

thread219-263651 someone knowledge ends where
someone else knowledge starts

 

[NEVERSLEEP]

cause binary file as only one line...
use binmode someone knowledge ends where
someone else knowledge starts

 

[MikeLacey]

you could try

open(F,'file');
while(<F>){
last if $. == 50045;
}
print;

This does go through all the lines in the file until it gets to the right one, but it's quite fast. At least as fast as using the head and tail unix trick.
Mike
______________________________________________________________________
&quot;Experience is the comb that Nature gives us after we are bald.&quot;

Is that a haiku?
I never could get the hang
of writing those things.

 

[NEVERSLEEP]

as said before it is a binary file !

open(&quot;<$file&quot;,DATA) || die &quot;\ndead $!&quot;;
binmode(DATA);
$all_data_is_one_line = <DATA>;
close(DATA); someone knowledge ends where
someone else knowledge starts

 

[ryen]

Oops, I'm sorry I didn't mean it was a binary file.. I just though I should make it a binary file and use the seek function to find a particular piece of data, but I need to learn more about writing binary files first. Sorry about the confusion, I didn't describe that very well.

but Mike, I'll definitely try that, it looks like the fastest solution so far, thanks a bunch.

 

[MikeLacey]

you might like to look at some database solutions, that will give you much faster access to each record

DBM files are good for smallish records that have a good unique key

Otherwise, MySQL is a good starting point for databases.

If you're on a Win PC, then Access files are quick to read using Perl as well. (not that I want to push you down *that* route) Mike
______________________________________________________________________
&quot;Experience is the comb that Nature gives us after we are bald.&quot;

Is that a haiku?
I never could get the hang
of writing those things.