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For 2023 - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!

I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
Variable formatting - beyond printf?

Posted by enquirer (enquirer), 22 November 2002
I am a perl newbie trying to format a  variable. The variable  is in the form of 00112233aa11 . I want to format this number to look like 00:11:22:33:aa:11 and I am having trouble doing that. I tried using sprintf function to no avail.  Any help is greatle appreciated.

Posted by admin (Graham Ellis), 22 November 2002

$var = "00112233aa11";
@parts = unpack("a2" x 6,$var);
print join ":",@parts;

Explanation - you can't do it with printf directly, as you need to separate out the various elements of your incoming string into separate variables.  Use unpack or substr to do this.  Then you can rejoing them using join, as you're always using the same separator character.  You could use printf once you have unpacked into separate scalars, but that would make for a slightly longer solution.

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