pack question

dash2 has asked for the wisdom of the Perl Monks concerning the following question:

Mystified once again by the documentation on "pack" which makes my brain hurt.

What I want to do is convert a number like 324789 into a string representation which is shorter and more mnemonic than "324789". E.g., convert it into hex and print the ASCII chars for each octet (??) Is there a quick and elegant way to do this?

Dave

dave hj~

Comment on pack question

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Re: pack question by btrott (Parson) on Jul 05, 2001 at 19:41 UTC
"Printing the ASCII chars" is not really equivalent to "converting to hex". Which do you want? :) If you want to print out 324789 as the binary representation of a long (in network order), for example, do this: `print pack "N", 324789;` [download] Say instead that you want to print it out in hex; then you can do this: `print unpack "H*", pack "N", 324789;` [download] Or you could use printf with the %x specifier.	[reply] [d/l] [select]
Re: pack question by jmcnamara (Monsignor) on Jul 05, 2001 at 20:11 UTC
As btrott says, it isn't quite clear what you are after. Perhaps something like this: `print hexdigits(324789), "\n"; sub hexdigits { join " ", map {sprintf "0x%02x", $_} unpack("C*", pack "V", $_ +[0]); } # Prints: 0xb5 0xf4 0x04 0x00` [download] Use pack "V" or "N" as required. John. --	[reply] [d/l]
Re: pack question by Arguile (Hermit) on Jul 06, 2001 at 06:23 UTC
I too was once mystifyed by pack, until I read Confession of a Perl Hacker. If you want to really understand the concept behind pack (painlessly) and how to use it effectively read through that discussion.	[reply]


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