Question

问题陈述 -

我们需要从字符串中提取一组连续出现的单词。

最简单的示例如下所示，具有预期的输入和输出。

set of words => "word1|word2|word3";

Input string => "i m word1 word2 and this is word3 word2 word1+ i am having this word2 word3.";"

Output => word1 word2
          word3 word2 word1
          word2 word3

注意 - 请注意，＆＃34; word1 +＆＃34;中没有空格。和＆＃34; word3。＆＃34;

请将此视为最简单的输入。复杂性可以是任何范围。意味着可以有多组单词（比如500个单词），我们需要找到一组从输入字符串中出现的单词。

我在javascript中执行此操作因此我尝试的内容如下所示。

var pattern = "word1|word2|word3";
var regobj = new RegExp('((('+pattern+')\\s?)+)', "g");

我的解决方案有什么问题？

For Input string => "i m word1word2 and this is word3word2 word1+ i am having this word2 word3.";"

it will give output as 
word1word2        -- wrong
word3word2 word1  -- wrong 
word2 word3

为什么我要这个？或实时用例..！

我想从复杂的expression.say

中提取单词数字

"one thousand two+three hundred four+1.3456+log(twenty)"

所以我需要提取

one thousand two
three hundred four
twenty

并且需要替换它们各自的数值等价物。

Answer 1

使用字边界：

\b(?:word1|word2|word3)\b

perl中的完整正则表达式：

my $str = 'i m word1word2 and this is word3 word2 word1+ i am having this word2 word3.';
my @l = ($str =~ /((?:\b(?:word1|word2|word3)\b(?:\s|\.))+)/g);
dump@l;

<强>输出：

("word3 word2 ", "word2 word3.")

使用最后一个表达式：

my $str = 'one thousand two+three hundred four+1.3456+log(twenty)';
my @l = ($str =~ /((?:\b(?:one|two|three|four|twenty|hundred|thousand)\b\s*)+)/g);
dump@l;

<强>输出：

("one thousand two", "three hundred four", "twenty")

Answer 2

对于问题的第二部分，您可以使用Lingua::EN::Words2Nums

#!/usr/bin/perl
use strict;
use warnings;
use Lingua::EN::Words2Nums;

my $string = "one thousand two+three hundred four+1.3456+log(twenty)";
my $re = qr(one|thousand|two|three|hundred|four|twenty);
my @groups = split(m/\+/,$string);
for my $group (@groups) {
    my @words = ($group =~ m/\b$re\b/g);
    next unless @words;
    my $number = words2nums("@words");
    print "@words => $number\n";
}

输出：

one thousand two => 1002
three hundred four => 304
twenty => 20

Answer 3

在Perl中，您可以使用拆分和 grep ：

perl -e '$w="word1|word2|word3"; while(<>){ print join " ", grep { /$w/ } split /\W/, $_ }' 
i m word1 word2 and this is word3 word2 word1+ i am having this word2 word3.
word1 word2 word3 word2 word1 word2 word3

在JavaScript中使用相同的功能：

var input="i m word1 word2 and this is word3 word2 word1+ i am having this word2 word3.";
var r=new RegExp("^(word1|word2|word3)$");
var wr=new RegExp("\\W");
var out = new Array();
var split = input.split(wr);
for( var i=0; i < split.length; i++) {
  if( split[i].match( r ) ){
    out.push(split[i]);
  }
} 
console.log(out);

输出：

["word1", "word2", "word3", "word2", "word1", "word2", "word3"]

正则表达式从字符串中提取一组单词

3 个答案: