Question

我想逐个字符地解析字符串。我使用perl来做到这一点。有没有办法我们可以从字符串的第一个字符开始，然后逐个字符循环。现在我已经将字符串拆分成一个数组，我就是厕所[ping通过数组。

$var="junk shit here. fkuc lkasjdfie.";
@chars=split("",$var);

但是不是在自身之前拆分整个字符串，是否有任何描述符指向字符串的第一个字符然后遍历每个字符？有没有办法做到这一点？

Answer 1

my $var = "junk sit here. fkuc lkasjdfie.";

while ($var =~ /(.)/sg) {
   my $char = $1;
   # do something with $char 
}

或

for my $i (1 .. length $var) {
  my $char = substr($var, $i-1, 1);
}

当有标记时，substr方法的效果优于while，

use Benchmark qw( cmpthese ) ;
my $var = "junk sit here. fkuc lkasjdfie." x1000;

cmpthese( -5, {
    "while" => sub{
      while ($var =~ /(.)/sg) {
         my $char = $1;
         # do something with $char 
      }
    },
    "substr" => sub{
      for my $i (1 .. length $var) {
        my $char = substr($var, $i-1, 1);
      }
    },
});

结果

         Rate  while substr
while  56.3/s     --   -53%
substr  121/s   114%     --

Answer 2

我不知道它是否比分割它更快但是你可以复制reverse它和chop它，直到它为空。

$a = "dude"; 
$b = reverse($a); 
for ($i = length($b) ; $i>0 ; $i--) {
  print chop $b; print "\n";'
}

Answer 3

这可以是脚本/正则表达式的骨架：

use strict;
use warnings;
use Data::Dumper qw(Dumper);

my $str = "The story of Dr. W. Fletcher who is a dentist. The hero of the community.";

my @sentences = split /(?<!(Dr| \w))\./, $str;
print Dumper \@sentences;

输出是：

$VAR1 = [
      'The story of Dr. W. Fletcher who is a dentist',
      undef,
      ' The hero of the community'
    ];

在Perl中逐字符解析字符串

3 个答案: