CODEWITHSUNDEEP
arraysperl
MCH
MCH

Reputation: 2214

Trouble reading file in array by line number in Perl

I am working with two files, so as I loop through one I need to look through part of another one, and the information I encounter in it will be sequential. So I thought the best way would be to keep track of the line number:
open(PARSED, "< file.txt") or die$!;
my @parsedFile = < PARSED >;
my $line = 0;
my $size = @parsedFile;
# This next part is in a loop, but the only important thing is this next line
print $parsedFile[$line];

Even as the value of $line increases, it prints nothing but if I do the following there is no problem:
foreach (@parsedFile){ print $_; }
 I have even tried a number of variations of trying to pull individual lines from @parsedFile but with no luck.

Upvotes: 0

Views: 543

Answers (3)

Hugmeir
Hugmeir

Reputation: 1259

The original problem was fixed by ysth, but if the files aren't huge (you are reading them into memory, so I'm guessing not), why not use Tie::File instead of all those shenanigans?

use strict;
use warnings;
use 5.010;
use Tie::File;

tie my @parsedFile, 'Tie::File', 'file.txt' or die "Error: $!";

my $line = 0;
print $parsedFile[$line];

Upvotes: 1

ysth
ysth

Reputation: 98388

<> is an incredibly picky operator that does two very different things based solely on precise syntax of what's in the brackets. < PARSED > (with the extra spaces) is glob("PARSED"), not readline(PARSED), so your array is just getting the single string "PARSED".

(Assuming your posted code is accurate; it really helps if you copy and paste your actual not-working code, not re-type parts of it; it helps even more if your copy-and-pasted code can be run exactly as is to demonstrate your problem.)

Note that:

use warnings;
open(PARSED, "< filename") or die $!;
my @lines = < PARSED >;

will give you a warning that PARSED is used only once, a big clue that the <> isn't doing what you think.

Upvotes: 7

codaddict
codaddict

Reputation: 455000

To load the file lines in an array you need to open the file first:

open F,'<','file.txt' or die;
my @parsedFile = <F>;

The way you are doing it results in array parsedFile which contains only one element "file.txt" which is the name of the file.

Upvotes: 0

Related Questions