Regex 在perl中从字符串中提取子字符串

我有一个字符串，如下所示：

downCircuit received;TOKENS START;{"action":'"UPDATE","device_id":"CP0027829","link_index":"101","name":"uplink101","description":"link1-0/0/3","priority":"200","status":"DOWN","wan_status":"DOWN","vlan":"4094","vlan_description":"vlan4094-intf","topic":"uplinks","stream_timestamp":"1547015547","aws_host":"attwifi-poc-central.arubathena.com","aws_timestamp":"1547015547","customer_id":"6666778917"};TOKENS END

---

我想从中提取link_index的值。i、 e.在这种情况下，输出应为101。有人能帮我从字符串中提取101吗。

你可以使用这样一个简单的正则表达式：

"link_index":"(\d+)"

#!/usr/bin/perl

use strict;
use warnings;
use feature 'say';

use JSON;

my $input = 'downCircuit received;TOKENS START;{"action":"UPDATE","device_id":"CP0027829","link_index":"101","name":"uplink101","description":"link1-0/0/3","priority":"200","status":"DOWN","wan_status":"DOWN","vlan":"4094","vlan_description":"vlan4094-intf","topic":"uplinks","stream_timestamp":"1547015547","aws_host":"attwifi-poc-central.arubathena.com","aws_timestamp":"1547015547","customer_id":"6666778917"};TOKENS END';

$input =~ s/.*START;//;
$input =~ s/;TOKENS END//;

my $data = JSON->new->decode($input);

say $data->{link_index};

然后从捕获组中获取内容

my $str = 'downCircuit received;TOKENS START;{"action":\'"UPDATE","device_id":"CP0027829","link_index":"101","name":"uplink101","description":"link1-0/0/3","priority":"200","status":"DOWN","wan_status":"DOWN","vlan":"4094","vlan_description":"vlan4094-intf","topic":"uplinks","stream_timestamp":"1547015547","aws_host":"attwifi-poc-central.arubathena.com","aws_timestamp":"1547015547","customer_id":"6666778917"};TOKENS END';
my $regex = qr/"link_index":"(\d+)"/mp;

if ( $str =~ /$regex/g ) {
  print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
  print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
  # print "Capture Group 2 is $2 ... and so on\n";
}

---

您可以使用反向引用：

打印$1，“\n”如果/“链接索引”：“（\d+）/

全面地说：

$string=q(downCircuit received;TOKENS START;{"action":'"UPDATE","device_id":"CP0027829","link_index":"101","name":"uplink101","description":"link1-0/0/3","priority":"200","status":"DOWN","wan_status":"DOWN","vlan":"4094","vlan_description":"vlan4094-intf","topic":"uplinks","stream_timestamp":"1547015547","aws_host":"attwifi-poc-central.arubathena.com","aws_timestamp":"1547015547","customer_id":"6666778917"};TOKENS END);
print $1,"\n" if $string =~ /"link_index":"(\d+)"/;

我有一根像下面这样的线

这里有一些JSON，前后都有额外的粗糙。因此，与其纠结于正则表达式，最好的办法是提取实际的JSON，然后使用它来处理它。大概是这样的：

"link_index":"(\d+)"

#!/usr/bin/perl

use strict;
use warnings;
use feature 'say';

use JSON;

my $input = 'downCircuit received;TOKENS START;{"action":"UPDATE","device_id":"CP0027829","link_index":"101","name":"uplink101","description":"link1-0/0/3","priority":"200","status":"DOWN","wan_status":"DOWN","vlan":"4094","vlan_description":"vlan4094-intf","topic":"uplinks","stream_timestamp":"1547015547","aws_host":"attwifi-poc-central.arubathena.com","aws_timestamp":"1547015547","customer_id":"6666778917"};TOKENS END';

$input =~ s/.*START;//;
$input =~ s/;TOKENS END//;

my $data = JSON->new->decode($input);

say $data->{link_index};

正如预期的那样，这将生成输出

101

---

注意：我想你的问题有错。至少，JSON中存在语法错误。我删除了您在“更新”之前使用的一个不匹配的引号字符，我尝试了此操作，但无效$LinkIndex=~/“link\u index”：“（\d+）/@Bindu转到并复制/粘贴我的代码。它很好用，你可以在那里测试。@Bindu很高兴它有效，记得把问题标记为已解决。你试过什么？什么不起作用？你得到了什么？你期待什么？你的代码有哪些地方不可用？它在哪里？