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how can we read each line from a file onto an array?

by Anonymous Monk
on Apr 18, 2001 at 09:57 UTC ( #73439=categorized question: print w/replies, xml ) Need Help??
Contributed by Anonymous Monk on Apr 18, 2001 at 09:57 UTC
Q&A  > files


Answer: how can we read each line from a file onto an array?
contributed by OeufMayo

my @lines = <FILE>;

But beware, as the perlfaq 5 says:

Whenever you see someone do this:

    @lines = <INPUT>;

You should think long and hard about why you need everything loaded at once. It's just not a scalable solution. You might also find it more fun to use the the standard DB_File module's $DB_RECNO bindings, which allow you to tie an array to a file so that accessing an element the array actually accesses the corresponding line in the file.

Answer: how can we read each line from a file onto an array?
contributed by tye

my @lines= do { local(*ARGV); @ARGV="filename.txt"; <> };
is one way to avoid having to open the file explicitly, check for errors, and report them.

Answer: how can we read each line from a file onto an array?
contributed by davorg

open FILE, '/path/to/file' or die "Can't open file: $!\n"; my @array = <FILE>;

All very simple :)

Answer: how can we read each line from a file onto an array?
contributed by abhishek_akj

my @lines = <FILE>
above loads the whole file at once in memory.

Instead, you can do something like

while(my $line=<FILE>){ do_something; }
This code will still traverse the whole file, so wont be faster but it will load only one line at a time in the memory - helpful if you want to parse 4GB file and have only 2 GB RAM ;)
Answer: how can we read each line from a file onto an array?
contributed by Clachair

use IO::File; open ($fhi, $fi) || die "$!, Couldn't open file $fi"; @lines = $fhi->getlines; foreach $lines(@lines) { # Select only those lines with a HTML cell bg color spec; if ($lines =~ /^\s*<td bgcolor/) {push @List, $lines; } } closedir ($fhi, $fi);
Clachair. Never lick a gift horse in the mouth.

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