# Assume the message is this
my $message = "me ss age";

# Use unpack to endcode the message one character at a time
my @character_code_send = unpack("C*", $message);

# You now have an array of ASCII values for each 
# character of the message.
# If you want to send the encoded message you
# must join all the element of the array
# together first

# No need to use join because " " does it for you
my $secret = "@character_code_send";

# So what gets sent is this
print "Message encoded = $secret\n";

# To decode the receiver has to split back out to an array
my @character_code_received = split ' ',$secret;

# And then use pack to decode each element back to string 
my $characters_received = pack("C*", @character_code_received);

# To get the answer !!
print "Message decoded = $characters_received";
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Thanks, I pretty much understand all of that now :) You made everything seem a lot easier, thanks! I have a question though. Are you saying split ' ',$secret; somehow breaks a scalar into an array of different values? If that's what it is, I understand that part of it, but what does ' ' have anything to do with it?

Thanks!

"Age is nothing more than an inaccurate number bestowed upon us at birth as just another means for others to judge and classify us"

sulfericacid

The first argument to split is a regex that describes the delimiters in the second argument. By specifying a space, you are telling split to break the string apart wherever it sees a space. So, split ' ',"A B C D" returns ('A','B','C','D'). If instead of space there were commas in your string, you could split ',',"A,B,C,D" instead. This would produce the same result.

---
print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';
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I think what is confusing you is "Where are the spaces coming from ?"


# If this is an array 
@a = ("A","B","C");

# then
print "@a";
# result =A B C ie. all spaced out

#
# because as the Camel book says
# Array variables are interpolated into double
# quoted strings by joining all the elements
# of the array with the delimiter specified
# in the $" variable (which is space by default)
#

#This however
print join ('',@a);

# result =ABC
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poj

Why did you change your template? You specified "C*" with the unpack example and "C" with the pack example. "C*" matches as many characters as are in the string. "C" only matches one character.

$str = pack('C*',48,49,50,51,52);
print "$str\n";
@chars = unpack('C*',$str);
print join(', ',@chars),"\n";
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... results in:

012345
48, 49, 50, 51, 52
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---
print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';
[download]

Sorry, that was a typo. I am using C* in both cases.

"Age is nothing more than an inaccurate number bestowed upon us at birth as just another means for others to judge and classify us"

sulfericacid

I read a lot of messages on here already on packing and unpacking on how everyone else is having problems understanding it as well. Does anyone have a good analogy or scenario on why it's used and how it works?