string - 从另一个字符串中提取所需的子字符串 -Perl

Question

我想从 Perl 中的一行中提取一个子字符串。让我举例说明：

fhjgfghjk3456mm   735373653736
icasd 666666666666
111111111111

在以上几行中，我只想提取 12 位数字。我尝试使用split功能：

my @cc = split(/[0-9]{12}/,$line);
print @cc;

但它所做的是删除字符串的匹配部分并将残差存储在@cc. 我希望打印与图案匹配的部分。我该怎么做？

Answer 1

您可以使用正则表达式来做到这一点：

#!/usr/bin/perl
my $string = 'fhjgfghjk3456mm 735373653736 icasd 666666666666 111111111111';
while ($string =~ m/\b(\d{12})\b/g) {
  say $1;
}

在此处测试正则表达式：http ://rubular.com/r/Puupx0zR9w

use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new(qr/\b(\d+)\b/)->explain();

The regular expression:

(?-imsx:\b(\d+)\b)

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    \d+                      digits (0-9) (1 or more times (matching
                             the most amount possible))
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

Answer 2

#!/bin/perl
my $var = 'fhjgfghjk3456mm 735373653736 icasd 666666666666 111111111111';
if($var =~ m/(\d{12})/) {
  print "Twelve digits: $1.";
}

Answer 3

$1 内置变量存储来自正则表达式的最后一个匹配项。此外，如果您对整个字符串执行正则表达式，它将返回整个字符串。最好的解决方案是在匹配项周围加上括号，然后打印 $1。

my $strn = "fhjgfghjk3456mm 735373653736\nicasd\n666666666666 111111111111";
$strn =~ m/([0-9]{12})/;
print $1;

这使得我们的正则表达式只匹配 12 位数字，然后我们返回匹配的 $1。

Answer 4

#!/usr/bin/env perl

undef $/;
$text = <DATA>;
@res = $text =~ /\b\d{12}\b/g;
print "@res\n";

__DATA__
fhjgfghjk3456mm   735373653736
icasd 666666666666
111111111111