Re: How to check if a file has more than one line?

Heres something I found out, if you assign an array to a variable, it will return the total amount of lines. Then you can do a simple if statement to see if it equals what you expect.

use strict;
use warnings;
use File::Slurp;

my @array = read_file("filename");

my $lines = @array;

if ( $lines == 1 ) {
    print "total amount of lines are 1";
}
else {
    print "file has $lines lines";
}
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Comment on Re: How to check if a file has more than one line? Download Code

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Re^2: How to check if a file has more than one line? by GrandFather (Saint) on Dec 05, 2014 at 02:01 UTC
That requires reading the whole file. For small files that's not a problem, but as a general thing you should only read as much at a time as you need. For that reason for loops and other techniques that read all the lines of a file into a list or array should be avoided unless you actually need random access to the whole file. Perl is the programming world's equivalent of English	[reply]
Re^3: How to check if a file has more than one line? by james28909 (Deacon) on Dec 05, 2014 at 04:14 UTC
What about something like this? lol `use strict; use warnings; open my $file, '<', "filename"; my $count_lines; my @array; while (<$file>) { $count_lines++; push @array, qw($_); last if ( $count_lines == 2 ); } my $lines = @array; print $lines; if ( $lines == 1 ) { print "this file only has 1 line"; } else { print "this file has 2 or more lines"; }` [download]	[reply] [d/l]
Re^4: How to check if a file has more than one line? by GrandFather (Saint) on Dec 05, 2014 at 04:40 UTC
You can be a little more succinct: `#!C:\Perl\bin use diagnostics; use strict; my $twoLines = 2 == grep {defined <DATA>} 1 .. 2; print "Two or more lines\n" if $twoLines; __DATA__ 1 2` [download] Perl is the programming world's equivalent of English	[reply] [d/l]