operators - What does =~ do in Perl? - Stack Overflow
man perlop "perlop - Perl operators and precedence" (at least in UNIX-like) answers this question: "Binary "=~" binds a scalar expression to a pattern match." – U. Windl Commented Apr 1, 2020 at 21:11
syntax - What are the differences between $, @, % in Perl variable ...
2011年4月5日 · Here the sigil changes to $ to denote that you are accessing a scalar, however the trailing [0] tells perl that it is accessing a scalar element of the array in _ or in other words, @_. – Eric Strom
variables - What is the meaning of @_ in Perl? - Stack Overflow
2010年12月30日 · perldoc perlvar is the first place to check for any special-named Perl variable info. Quoting: @_: Within a subroutine the array @_ contains the parameters passed to that subroutine. More details can be found in perldoc perlsub (Perl subroutines) linked from the perlvar: Any arguments passed in show up in the array @_.
How does double arrow (=>) operator work in Perl?
2016年2月2日 · The => operator in perl is basically the same as comma. The only difference is that if there's an unquoted word on the left, it's treated like a quoted word. The only difference is that if there's an unquoted word on the left, it's treated like a quoted word.
What's the use of <> in Perl? - Stack Overflow
2015年3月13日 · So, if the shell is handing you a bunch of file names, and you'd like to go through each one's data in turn, perl's <> operator gives you a nice way of doing that...it puts the next line of the next file (or stdin if no files are named) into $_ (the default scalar). Here is a poor man's grep: while(<>) { print if m/pattern/; } Running this script:
What does the -> arrow do in Perl? - Stack Overflow
2011年2月6日 · Perl arrow operator has one other use: Class−>method invokes subroutine method in package Class. though it's completely different than your code sample. Only including it for completeness for the question in the title.
What does exactly perl -pi -e do? - Stack Overflow
2015年1月25日 · You can inspect the code actually used by Perl with the core module B::Deparse. This compiler backend module is activated with the option -MO=Deparse.
operators - What is the difference between "||" and "or" in Perl ...
2019年11月10日 · From Perl documentation:. OR List operators. On the right side of a list operator, it has very low precedence, such that it controls all comma-separated expressions found there.
What is the difference between Perl's ( or, and ) and ( ||, && ) short ...
2012年9月25日 · I came to Perl 5 from C and Perl 4 and always used || until I saw more scripts using or and I liked the way it looked. But as the above quiz shows, it's not without its pitfalls for the unwary. But as the above quiz shows, it's not without its pitfalls for the unwary.
How do you round a floating point number in Perl?
With 5.004, the Math::Trig module (part of the standard Perl distribution) > implements the trigonometric functions. Internally it uses the Math::Complex module and some functions can break out from the real axis into the complex plane, for example the inverse sine of 2.