in reply to Select data between a START and END pattern
Although dragonchild gives a good example of .., here's a more general explanation, along with the difference between .. and ...
First of all, there is use of .. in a list context:
Then there's the unrelated use in a scalar context. It only makes sense in a loop.@a = 1 .. 7;
is equivalent to:while (something) { if (EXPRSTART .. EXPREND) { doit(); } }
Okay? Now for three dots:$inmatch = 0; while (something) { if (!$inmatch && EXPRSTART) { $inmatch = 1; } if ($inmatch) { doit(); } if ($inmatch && EXPREND) { $inmatch = 0; } }
is equivalent to:while (something) { if (EXPRSTART ... EXPREND) { doit(); } }
Subtle difference. To see it in action, compare:$inmatch = 0; while (something) { $wasinmatch = $inmatch; if (!$inmatch && EXPRSTART) { $inmatch = 1; } if ($inmatch) { doit(); } if ($wasinmatch && EXPREND) { $inmatch = 0; } }
withwhile (<>) { print if /A/ .. /B/ }
on this input filewhile (<>) { print if /A/ ... /B/ }
Here's some text before Some text with an A some lines in the middle 1 some lines in the middle 2 some lines in the middle 3 Some text with a B some useless lines 1 some useless lines 2 some useless lines 3 A line with both an A and a B some lines after the line with both 1 some lines after the line with both 2 some lines after the line with both 3 Once again, text with a B more useless lines 1 more useless lines 2 more useless lines 3
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Re2: Select data between a START and END pattern
by dragonchild (Archbishop) on May 01, 2003 at 21:12 UTC |
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