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I am a beginner of perl scripting. I know hyphen (-) is used to specify the range.
But what if it is mentioned in the beginning of the expression?
Example:
if ($_ =~ /-\n/)
//do something
How to interpret the above code?
"if the parameter is equal to a range of newline" ? (No, that is weird understanding :-/)
Please help.
761
In posix-ere and other regex flavors, outside a character class ( [...] ), + acts as a quantifier meaning "one or more, but as many as possible, occurrences of the quantified pattern*. E.g. in javascript, s. replace(/\++/g, '-') will replace a string like ++++ with a single - .
Basically (0+1)* mathes any sequence of ones and zeroes. So, in your example (0+1)*1(0+1)* should match any sequence that has 1. It would not match 000 , but it would match 010 , 1 , 111 etc. (0+1) means 0 OR 1.
the * means "zero or more times" the parentheses group and capture, the \ allows you to match a special character (like the dot or the star)
Outside of [] - means "-" as far as I know, it only indicates a range within a [] block.
Here is a more complete answer I found
How to match hyphens with Regular Expression? (look at the second answer)
So the expression should match a - followed by a newline or line ending with -
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