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From: marcl@ESD.3Com.COM (Marc Lavine)
Newsgroups: comp.lang.perl
Subject: Re: Splitting by character count in perl?
Message-ID: <marcl.668420845@cook.ESD.3Com.COM>
Date: 8 Mar 91 08:27:25 GMT
References: <17806@milton.u.washington.edu> <1991Mar7.002047.5121@uvaarpa.Virginia.EDU>
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djo7613@milton.u.washington.edu (Dick O'Connor) writes:
>Our old program copied the first 78 characters on a line to the output file
>after prepending and appending the character 'A'.  Characters 79-150 were
>written to line 2 of the output file with prepended and appended 'B'.  A
>simple routine glued things back together at the other end.

eichin@athena.mit.edu (Mark W. Eichin) writes:
>	As for your particular example, the one-liner:
>perl -ne '@two=unpack("a78a72",$_); print "A",$two[0],"A\nB",$two[1],"B\n";'

I just started hacking with Perl last week (and think it's great -- thanks
for another wonderful tool, Larry), but I'm a long-time fan of regular
expressions (in the distant past, I used to edit files with "ex").  I
really like having Perl's "fancy" regular expressions available.  So,
here's a different solution to the problem using only regular
expressions (which should be quite fast):

To split the lines use:
	perl -pe 's/^(.{78})(.{72})$/A\1A\nB\2B/'

And to join them use:
	perl -pe 's/^A(.{78})A\n/\1/; s/^B(.{72})B$/\1/;'

(which came out very similar to Randal Schwartz's suggestion of:
	perl -pe 's/^A(.*)A\n$/$1/ || s/^B(.*)B\n$/$1\n/;'
)


BTW, I came up with the following motto for Perl:

	Perl: Kitchen sink included.
--
Marc Lavine			Broken: marcl%3Com.Com@sun.com
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