perl 正则命名捕获

#!/usr/bin/perl -w 
=pod 
命名捕获--给匹配上的内容加上标签 

捕获到的内容都会保存在%+散列中，这个散列的key为对应的标签； 

方便之处就是利于程序扩展和阅读，不用繁琐的一个一个去数括号来获取匹配变量 
=cut 


zjtest7-frontend:/root/perl# cat a2.pl 
use strict; 
my $str = "jack and rose"; 
if ($str =~ /(?<first>S+) (and|or) (?<second>S+)/) { 
    my ($first, $second) = ($+{first}, $+{second}); 
    print "$first
$second
";  # jack, rose 
} 


zjtest7-frontend:/root/perl# perl a2.pl 
jack
rose


s  空格,和 [
	
f] 语法一样  
s+ 和 [
	
f]+ 一样  
S  非空格,和 [^
	
f] 语法一样  
S+ 和 [^
	
f]+ 语法一样  

/******************************************************

zjtest7-frontend:/root/perl# cat a1.pl 
my $str="begin 123.456 end";

if ($str =~/(?<first>S+)s+(?<second>S+)s+(?<third>S+)/)
  {
  my ($first, $second,$third) = ($+{first}, $+{second},$+{third});
  print "$first
$second
$third
";  # jack, rose 
} 

zjtest7-frontend:/root/perl# perl a1.pl 
begin
123.456
end


zjtest7-frontend:/root/perl# cat a3.pl 
my $str="begin 123.456 end";
if ($str =~/s+(?<request_time>d+(?:.d+)?)s+/){
   my ($request_time) = ($+{request_time});
   print $request_time."
";};

zjtest7-frontend:/root/perl# perl a3.pl 
123.456