I have little experience about perl, trying to read simple text file line by line and put all objects in to array. Could you please help ?
Text File:
AAA
BBB
CCC
DDD
EEE
Needs to have access for each object in array by index to get access for DDD element for example.
THX
Try this:
use strict;
use warnings;
my $file = "fileName";
open (my $FH, '<', $file) or die "Can't open '$file' for read: $!";
my @lines;
while (my $line = <$FH>) {
push (@lines, $line);
}
close $FH or die "Cannot close $file: $!";
print @lines;
To access an array in Perl, use [] and $. The index of the first element of an array is 0. Therefore,
$lines[3] # contains DDD
see more here : http://perl101.org/arrays.html
my @lines = <FH> would do it. There is no good reason to individually push each line ... unless you are doing something to the lines as your read them. Even just my @files = <>; would be sufficient.open(my $fh, '<', $qfn)
or die("Can't open $qfn: $!\n");
my @a = <$fh>;
chomp @a;
As for the last paragraph, I don't know if you mean
$a[3]
or
my @matching_indexes = grep { $_ eq 'DDD' } 0..$#a;
Your "requirements" here seem extremely minimal and I agree with @ikegami it's hard to tell if you want to match against text in the array or print out an element by index. Perhaps if you read through perlintro you can add to your question and ask for more advanced help based on code you might try writing yourself.
Here is a command line that does what your question originally asked. If you run perldoc perlrun on your system it will show you the various command line switches you can use for perl one-liners.
-0400 - slurps input-a - autosplits the file into an array called @F using a single white space as the split character. -n - run in an implicit while (<>) { } loop that reads input from the file on -E - execute the script between ' 'So with lines.txt equal to your text file above:
`perl -0400 -a -n -E 'say $F[3];' lines.txt`
outputs: DDD
