Question

如果我可以为一个模式匹配做两件不同的事情，我会徘徊：我正在阅读包含以下行的文件：

(   1,<2010-01-12 15:19:51.32 +0100>,<marc>,<telescope1>,

我正在尝试这个策略：

open(FILE, "<tmpinp.txt");  
while (<FILE>){
    {$expstart = timelocal($6,$5,$4,$2,($3-1),$1) && $usr=$7} if
          /.+1,<(\d{4})-(\d{2})-(\d{2})\s(\d{2}):(\d{2}):(\d{2}).*>,<(\S+)>,<(\S+)>.+\n/;
    };
close(FILE);
};

因此我想获得纪元时间和用户名（本例中为marc）在一次运行。它只是不起作用。任何帮助！？

Thanx很多！

Answer 1

最明确的方法是使用if的非后缀形式：

while (<FILE>){
   if (/.+1,<(\d{4})-(\d{2})-(\d{2})\s(\d{2}):(\d{2}):(\d{2}).*>,<(\S+)>,<(\S+)>.+\n/) {
      # this is a block; you can put as many statements in here as you want
      $expstart = timelocal($6,$5,$4,$2,($3-1),$1);
      $usr = $7;
   }
}

如果你真的，真的想要出于某种原因使用postfix if，你仍然可以将它用于一个块，感谢do：

while (<FILE>){
   do {
      # this is a block; you can put as many statements in here as you want
      $expstart = timelocal($6,$5,$4,$2,($3-1),$1);
      $usr = $7;
   } if /.+1,<(\d{4})-(\d{2})-(\d{2})\s(\d{2}):(\d{2}):(\d{2}).*>,<(\S+)>,<(\S+)>.+\n/;
}

或者您可以以某种深奥的方式将两个陈述合并为一个。这对于在非常紧密的循环内微观优化条件非常有用。例如，您可以使用逗号运算符组合两个分配：

while (<FILE>){
   ($expstart = timelocal($6,$5,$4,$2,($3-1),$1)), ($usr = $7)
      if /.+1,<(\d{4})-(\d{2})-(\d{2})\s(\d{2}):(\d{2}):(\d{2}).*>,<(\S+)>,<(\S+)>.+\n/;
}

或者，如果您知道timelocal将始终返回单个标量值（从不返回零或多个值的列表），那么您可以使用列表赋值来设置$expstart和{{ 1}}：

$usr

或者如果您知道while (<FILE>){ ($expstart, $usr) = (timelocal($6,$5,$4,$2,($3-1),$1), $7) if /.+1,<(\d{4})-(\d{2})-(\d{2})\s(\d{2}):(\d{2}):(\d{2}).*>,<(\S+)>,<(\S+)>.+\n/; }将始终返回“true”值（即不是0，或空字符串或undef），您可以在尝试时使用timelocal：

&&

TIMTOWTDI。

Answer 2

这个怎么样：

#!/usr/bin/perl                                                                                                                                                                                                                                                
use strict;
use warnings;
use Time::Local;

open(FILE, "<tmpinp.txt");

while (<FILE>){
    if ($_ =~ /^.+1,<(\d{4})-(\d{2})-(\d{2})\s(\d{2}):(\d{2}):(\d{2}).*?>,<(\S+)>,<(\S+)>.+$/) {
        print join(' => ', timelocal($6,$5,$4,$2,$3-1,$1), $7) . "\n";
    }
}

close(FILE);

打印：

1291213191 => marc

如果模式在Perl中匹配，则为double task

2 个答案: