regex - Perl Regex多个匹配项

我正在寻找将表现如下的正则表达式:



我的主意是

    while($string =~ m/(([a-zA-Z])([a-zA-Z]))/g) {
        print "$1-$2 ";
    }

但这确实有些不同。

最佳答案

这很棘手。您必须捕获它，保存它，然后强制回溯。

您可以通过以下方式做到这一点:

use v5.10;   # first release with backtracking control verbs

my $string = "hello, world!";
my @saved;

my $pat = qr{
    ( \pL {2} )
    (?{ push @saved, $^N })
    (*FAIL)
}x;

@saved = ();
$string =~ $pat;
my $count = @saved;
printf "Found %d matches: %s.\n", $count, join(", " => @saved);

产生这个:

Found 8 matches: he, el, ll, lo, wo, or, rl, ld.

如果您没有v5.10或感到头疼，可以使用以下命令:

my $string = "hello, world!";
my @pairs = $string =~ m{
  # we can only match at positions where the
  # following sneak-ahead assertion is true:
    (?=                 # zero-width look ahead
        (               # begin stealth capture
            \pL {2}     #       save off two letters
        )               # end stealth capture
    )
  # succeed after matching nothing, force reset
}xg;

my $count = @pairs;
printf "Found %d matches: %s.\n", $count, join(", " => @pairs);

产生与以前相同的输出。

但是您可能仍然会头疼。

关于regex - Perl Regex多个匹配项，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/15279235/