A silly reg exp question

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

Replies are listed 'Best First'.
Re: A silly reg exp question by tobyink (Canon) on Jan 16, 2012 at 14:24 UTC
`s{ (\d+) } { '-' x $1 }gex;` [download] Update: I'll add that this allows arbitrary integers in the string, including integers with two or more digits. Assuming that you're sticking to standard sized chess boards, the following is probably sufficient... `s{ ([1-8]) } { '-' x $1 }gex;` [download]	[reply] [d/l] [select]
Re^2: A silly reg exp question by chessgui (Scribe) on Jan 16, 2012 at 15:16 UTC
Tested: OK. This is the most general and readable code so I will use this in my prog.	[reply]
Re: A silly reg exp question by Corion (Patriarch) on Jan 16, 2012 at 14:13 UTC
You might want to take a look at the `/e` modifier for regular expressions in perlre.	[reply] [d/l]
Re^2: A silly reg exp question by chessgui (Scribe) on Jan 16, 2012 at 15:01 UTC
In perlre the 'e' modifier is not explained. You should have directed me to perlop. Now it is clear that /e rather than replacing the match with a string it replaces it with an (e)xpression evaluated.	[reply]
Re: A silly reg exp question by JavaFan (Canon) on Jan 16, 2012 at 14:37 UTC
A couple of ways (all untested): `s/([1-8])/"-" x $1/eg; s/1/-/g, s/2/--/g, s/3/---/g, s/4/----/g, s/5/-----/g, s/6/------/g, s +/7/-------/g, s/8/--------/g; my @x = map {"-" x $_} 0..8; s/([1-8])/$x[$1]/g; 1 while s/([2-8])/-@{[$1-1]}/g; s/1/-/g; s/8/7-/g; s/7/33-/g; s/6/5-/g; s/5/22-/g; s/4/3-/g; s/3/11-/g; s/2/1-/ +g; s/1/-/g;` [download]	[reply] [d/l]
Re^2: A silly reg exp question by AnomalousMonk (Archbishop) on Jan 16, 2012 at 20:42 UTC
`s/8/7-/g; s/7/33-/g; s/6/5-/g; s/5/22-/g; s/4/3-/g; s/3/11-/g; s/2/1-/ +g; s/1/-/g;` [download] This version certainly seems to work, but is it lazy, crazy, peevish, peccant, or...? I think it's the version I would choose if I hated the person who would be maintaining my code! Update: ++ for the whole reply for diversity and perversity!	[reply] [d/l]
Re^3: A silly reg exp question by JavaFan (Canon) on Jan 16, 2012 at 20:58 UTC
Feel free to replace the semicolons (except the last) with xors for even more perversity.	[reply]
Re^4: A silly reg exp question by AnomalousMonk (Archbishop) on Jan 17, 2012 at 01:05 UTC
Re^2: A silly reg exp question by chessgui (Scribe) on Jan 16, 2012 at 14:48 UTC
s/1/-/g, s/2/--/g, s/3/---/g, s/4/----/g, s/5/-----/g, s/6/------/g, s/7/-------/g, s/8/--------/g; This is the exact way I have done it :). When you are lazy you end up with code like this. To be sure: this works.	[reply]
Re: A silly reg exp question by TJPride (Pilgrim) on Jan 16, 2012 at 22:23 UTC
`$_ = 'p1r4k/8'; s/(\d+)/'-'x$1/eg; print;` [download] Output: `p-r----k/--------`	[reply] [d/l] [select]