From time to time, I saw people wondering why a piece of code does not work, just because they have “garbage” in their data. People really need a tool to inspect what their strings contain, so I just created this StringInspector class, and hope it helps.

This is how to use it: 
use StringInspector;
use strict;
my $inspector = new StringInspector;
$inspector->inspect("abcdefghijkl");
$inspector->display();

[download]
This is the package itself: 
package StringInspector;

use Hash::Util qw(lock_keys);
use strict;

sub new {
    my $self = {};
    $self->{SUSPECT} = "";
    bless $self;
    lock_keys(%{$self});
    return $self;
}

sub inspect {
    my ($self, $string) = @_;
    $self->{SUSPECT} = $string;
}

sub display {
    my $self = shift;
    for (my $index = 0; $index <= length $self->{SUSPECT}; $index += 1
+0) {
        my $ten= substr($self->{SUSPECT}, $index, 10);
        my $numbers = "";
        my $chars = "";
        for (my $this_char = 0; $this_char < length $ten; $this_char +
++) {
            my $ascii = ord(substr($ten, $this_char, 1));
            $numbers .= sprintf("0x%0x  ", $ascii);
            $chars .= (($ascii >= 32) && ($ascii <= 126)) ? substr($te
+n, $this_char, 1) : "."; 
        }
        print $numbers;
        print " " x (60 - length $numbers);
        print " " x 5;
        print $chars;
        print "\n";
    }
}

1;

[download]

Replies are listed 'Best First'.
Re: Is there any garbage chars in your data?
by cchampion (Curate) on Mar 26, 2003 at 00:04 UTC

    Wouldn't this be a lot quicker and simpler?

    #!/usr/bin/perl -w
use strict;

my $string = "abc12defghi\013jkl";

for (split //, $string) {
    print /[[:print:]]/ ? $_ : sprintf " (0x%02x) ", ord $_ ;
}
print "\n";
__END__
abc12defghi (0x0b) jkl

    [download]
[reply]
[d/l]
[reply]
[d/l]
      Thank you, modified my code to include your split //. However, I choose not to use :print:, as that would have problem with Unicode, instead I added ‘use bytes’ to my code.

      I still like my own output format better ;-), but I added code to allow user to configure the format (a little bit). 
      package StringInspector;

use Hash::Util qw(lock_keys);
use strict;

sub new {
    my $self = {};
    $self->{SUSPECT} = "";
    $self->{BYTES_IN_ROW} = 10;
    $self->{COLUMNS_BETWEEN_PANES} = 5;
    bless $self;
    lock_keys(%{$self});
    return $self;
}

sub inspect {
    my ($self, $string) = @_;
    $self->{SUSPECT} = $string;
}

sub bytes_in_row {
    my $self = shift;
    if (@_) {
        $self->{BYTES_IN_ROW} = shift;
    }
    return $self->{BYTES_IN_ROW};
}

sub columns_between_panes {
    my $self = shift;
    if (@_) {
        $self->{COLUMNS_BETWEEN_PANES} = shift;
    }
    return $self->{COLUMNS_BETWEEN_PANES};
}

sub display {
    use bytes;
    my $self = shift;
    for (my $index = 0; $index <= length $self->{SUSPECT}; $index += $
+self->{BYTES_IN_ROW}) {
        my ($numbers, $chars) = ("", "");
        foreach my $this_char (split(//, substr($self->{SUSPECT}, $ind
+ex, $self->{BYTES_IN_ROW}))) {
            my $ascii = ord($this_char);
            $numbers .= sprintf("0x%0x  ", $ascii);
            $chars .= (($ascii >= 32) and ($ascii <= 126)) ? $this_cha
+r : "."; 
        }
        print $numbers;
        print " " x (6 * $self->{BYTES_IN_ROW} - length $numbers);
        print " " x $self->{COLUMNS_BETWEEN_PANES};
        print $chars;
        print "\n";
    }
}

1;


testing code:
use StringInspector;
use strict;
my $inspector = new StringInspector;
$inspector->bytes_in_row(3);
$inspector->columns_between_panes(40);
$inspector->inspect("abcdefghi" . chr(400) ."jkl");
$inspector->display();

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[reply]
[d/l]

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