Perl Hash + While add elements

Question

I need store each element in the first column where are the privileges in keys and value in the file, i did this but I do not understand.

it's content in my file "file-privilege"

-rw-rw-r--. file-privilege
-rw-rw-r--. file-selinux
-rwxrwxrwx. funcion-split-join.pl
-rwxrwxr-x. hash2.pl
-rw-rw-r--. hash3.pl
-rwxrwxr-x. hash.pl
-rwxrwxr-x. inthashfile.pl
-rw-rw-r--. ls
-rwx------. probando.pl

the code in perl.

%pr_file = ();
open(WHO, "file-privilege");
while (<WHO>) {
    ($privilege, $file) = split ;
    push( @{$pr_file{$privilege}}, $file );
}

this output.

-rwx------. = ARRAY(0x83bb7f0)
-rw-rw-r--. = ARRAY(0x83a06f8)
-rwxrwxr-x. = ARRAY(0x83bb780)
-rwxrwxrwx. = ARRAY(0x83bb750)

I need:

key = value

-rw-rw-r--. = file-privilege

etc...

any idea?

tripleee · Accepted Answer · 2012-09-02 16:40:55Z

3

The same key maps to multiple values. You need to dereference the array reference just like when you add a value; or use a scalar which only remembers the last (or first, or a random) value.

Anyway, the code you have shown us is correct; the problem is in the code which prints out the values, which you have not provided. But something like this:

for my $priv (keys %pr_file) {
    for my $file (@{$pr_file{$priv}}) {
        print "$priv => $file"; # Already contains trailing newline
    }
}

By the by, you should probably use Perl's built-in stat() function rather than try to parse ls output.

edited Sep 2, 2012 at 16:40

answered Sep 2, 2012 at 16:30

tripleee

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1 Comment

opmeitle Over a year ago

sub noc {foreach $user (sort keys %pr_file) { print "$user @{$pr_file{$user}}\n"; }} noc

DVK · Accepted Answer · 2012-09-02 17:20:26Z

2

Without seeing the code, you are probably doing:

print "$privilege = $pr_file{$privilege}\n";

Since you are storing a list of filenames in an array reference $pr_file{$privilege}, this code uses default stringification of an array reference, by printing "ARRAY(address)".

When you are printing the results, you need to stringify you arrayref of file names in a more useful format yourself:

print "$privilege = $pr_file{$privilege}->[0]\n"; # Print the first file in the list

print "$privilege = $pr_file{$privilege}->[-1]\n"; # Print the last file in the list

my $files_string = join(",", @{ $pr_file{$privilege} })); #Comma separated files
print "$privilege = $files_string\n"; # Print all files, comma separated

my @files = @{ $pr_file{$privilege} }); # Dereference the array ref into array
print "$privilege = @files\n"; # Print all files, space separated. 
                               # Uses default stringification of an array

edited Sep 2, 2012 at 17:20

answered Sep 2, 2012 at 16:34

DVK

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1 Comment

Ilmari Karonen Over a year ago

You can even do print "$privilege = @{ $pr_file{$privilege} }"; directly.

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