perl

问题 I gave a list of globs and one string to Perl's glob function. The globs were treated as expected but the string is always found. For example: $ ls foo $ perl -le '@files=glob("*bar"); print @files' ## prints nothing, as expected $ perl -le '@files=glob("bar"); print @files' bar As you can see above, the second example prints bar even though no such file exists. My first thought is that it behaves like the shell in that when no expansion is available, a glob (or something being treated as a

问题 I gave a list of globs and one string to Perl's glob function. The globs were treated as expected but the string is always found. For example: $ ls foo $ perl -le '@files=glob("*bar"); print @files' ## prints nothing, as expected $ perl -le '@files=glob("bar"); print @files' bar As you can see above, the second example prints bar even though no such file exists. My first thought is that it behaves like the shell in that when no expansion is available, a glob (or something being treated as a

问题 I can't find an authoritative/comprehensive description of where CPAN installs its files. I assume there must be a set of rules and that it's not as simple as "XYZ directory" because, for example, multiple users on a Linux box can run CPAN even though there's a single Perl installation and it still somehow works. So, what are those rules? A second part of this question: The documentation for the PERL5LIB environment variable says that it is "A list of directories in which to look for Perl

问题 I can't find an authoritative/comprehensive description of where CPAN installs its files. I assume there must be a set of rules and that it's not as simple as "XYZ directory" because, for example, multiple users on a Linux box can run CPAN even though there's a single Perl installation and it still somehow works. So, what are those rules? A second part of this question: The documentation for the PERL5LIB environment variable says that it is "A list of directories in which to look for Perl

问题 Basically this is the result of my programming on google for last half an hour trying to achieve a simple thing: pick up user inputs from STDIN and write them into a structured XML file as the output, below is my ugly code: #!/bin/perl print "img URL = ? "; $img = <>; chomp($img); print "filename = ? "; $filename = <>; chomp($filename); # now write xml with inserted contents to a file: open (CARDFILE, ">>$filename"); print CARDFILE "<card>\r\n"; print CARDFILE " <img>$img</img>\r\n"; print

问题 Is there a way to get a sub-hash? Do I need to use a hash slice? For example: %hash = ( a => 1, b => 2, c => 3 ); I want only %hash = ( a => 1, b => 2 ); 回答1: Hash slices return the values associated with a list of keys. To get a hash slice you change the sigil to @ and provide a list of keys (in this case "a" and "b" ): my @items = @hash{"a", "b"}; Often you can use a quote word operator to produce the list: my @items = @hash{qw/a b/}; You can also assign to a hash slice, so if you want a

问题 On Windows 10, I installed geckodriver.exe from https://github.com/mozilla/geckodriver/releases and Selenium Server from https://www.selenium.dev/downloads/ I started the server successfully from the command prompt: > java "-Dwebdriver.gecko.driver=geckodriver/geckodriver.exe" -jar selenium-server/selenium-server-standalone-3.141.59.jar -host localhost -port 4444 20:00:48.591 INFO [GridLauncherV3.parse] - Selenium server version: 3.141.59, revision: e82be7d358 20:00:53.896 INFO

问题 On Windows 10, I installed geckodriver.exe from https://github.com/mozilla/geckodriver/releases and Selenium Server from https://www.selenium.dev/downloads/ I started the server successfully from the command prompt: > java "-Dwebdriver.gecko.driver=geckodriver/geckodriver.exe" -jar selenium-server/selenium-server-standalone-3.141.59.jar -host localhost -port 4444 20:00:48.591 INFO [GridLauncherV3.parse] - Selenium server version: 3.141.59, revision: e82be7d358 20:00:53.896 INFO

问题 I have a file called test.txt with the following: > Last login: Mon Jul 13 05:09:33 2020 You have mail. > ****************************** > cat, you have just logged into machine sampleserver2 > ****************************** > > -------------------------------------------------------------- > | To switch environments later, run: | > | | > | change | > | | > -------------------------------------------------------------- > > > Current Dir => /apps/users/cat Oracle SID: SAMPLE > cat

问题 I'm building a Python program that also runs a Perl script from within. Is there a way to create an executable where the user of my program doesn't have to install Perl but has Python? 回答1: Here is an example of how you can use pp to build an executable (that does not depend on the perl executable being installed). I am using perlbrew with perl version 5.30 on Ubuntu 20.04. First install pp : cpanm PAR::Packer Create a test Perl script hello.pl (you may need to install Path::Tiny first): use