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Re: I don't understand a piece of this code

by Albannach (Prior)
on Jun 18, 2012 at 03:40 UTC ( #976732=note: print w/ replies, xml ) Need Help??


in reply to I don't understand a piece of this code

I rather think of qw as quote whitespace since what it does is break up the subject string using whitespace as separators. So the string inside the qw() is broken into 3 pieces, not 3 words as in this case each resulting piece contains 2 words and some square brackets. See perlop under Quote and Quote-like operators.

The next think you need to know is that \Q and \E are allowing you to use the content of the variable $what as literal text without interpreting any special characters, which in this case are the square brackets. Have a look at perlre to see what [box] means inside a regular expression.

So in summary it is looking for the string [box] including the square brackets, withing the 3 separate strings in[box], out[box], and white[sox], and prints matches.

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Re^2: I don't understand a piece of this code
by bitingduck (Friar) on Jun 18, 2012 at 03:49 UTC

    That's how I initially learned it as well, but perldoc.perl.org j ust says "quote a list of words" where you have to sort of liberally accept that a word is letters separated by whitespace. "Quote with whitespace" makes more sense to me than "quote whitespace", but it mostly just matters that it works as advertised.

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