用php将正则表达式匹配多个完整单词

Question

I'm implementing a "Tags" feature in our custom product management system. Each product has a comma seperated list of tags associated. We have a "tag search" with check boxes. The user can check multiple tags and it will filter with ajax with all the selected tags, so all tags need to be matched together. Example.

Tags: Tag1,Tag2,Tag3

#1-product-tags: Tag3,Tag10,Tag2
#2-product-tags: Tag1,Tag3,Tag10
#3-product-tags: Tag5,Tag1,Tag3
#4-product-tags: Tag8,Tag4,Tag20
#5-product-tags: Tag20,Tag100,Tag500

When filtering with the above tags checked, I expect to return #1,#2,#3 only because the given tags are listed in the product-tags column of these products.

Im currently trying to use regular expressions by dynamically creating a regex when the user checks the tags. In order to qualify as a match, the product must have all tags checked. Im generating this like so:

   <?php 
       //empty collection array to fill with product loop
       $collection = array();

       //dynamically generated regex
       $regex = "\b" . $tag1 . "|" . $tag2 . "|" . $tag3 . "\b/i";

       //loop through each product and throw matches to collection
       foreach($products as $product) {
         if(preg_match($regex,$product->tags)) {
            array_push($collection,$product);
         }
       }
    ?>

I am not getting the expected result doing it this way. What is the best way I can get my expected result. Im not too great with Regular Expressions but I am learning.

Answer 1

I'm assuming the tags are stored in an array as comma-separated strings. If that's the case, you can split them into individual arrays using explode() and then loop through the array and use array_intersect() to see if any of the sub-arrays have all the values in the $search array:

$search = ['Tag1', 'Tag2', 'Tag3'];

$taglist = array_map(function ($v) { return explode(',', $v); }, $tags);

foreach ($taglist as $sub) {
    if (count(array_intersect($sub, $search)) == count($search)) {
        $products[] = implode(',', $sub);
    }
}

Not only this approach is efficient, it is more flexible. It will not be a problem if you have multiple conditions to check for. If you were to do this with a regex, you'd have a hard time crafting the regex and chances are it will be a lot slower than this simple split & loop solution.

For the tags in the question, this would return nothing — $products array would be empty.

Demo

Answer 2

If you still want to go with the regex i recommand some regex like

Tag2(,.*)?$|Tag1(,.*)?$/i

See live example here

With new specifications you have to use positive lookahead

(?=(((Tag1|Tag2|Tag3)(,.*)?$)))

See live example here

Answer 3

I think your regular expression has 2 small details to consider. 1 - missing the first delimiter character / 2 - group in brackets the options you want to choose one of them

$regex = "/\b(" . $tag1 . "|" . $tag2 . "|" . $tag3 . ")\b/i";


try with this code to see my result.
<?php
 $tag1 = 'Tag1';
 $tag2 = 'Tag2';
 $tag3 = 'Tag3';

$arr = array();
$arr["#1-product-tags"] = "Tag3,Tag10,Tag2";
$arr["#2-product-tags"] = "Tag1,Tag3,Tag10";
$arr["#3-product-tags"] = "Tag5,Tag1,Tag3";
$arr["#4-product-tags"] = "Tag8,Tag4,Tag20";
$arr["#5-product-tags"] = "Tag20,Tag100,Tag500";
var_dump($arr);

//empty collection array to fill with product loop
$collection = array();

//dynamically generated regex
$regex = "/\b(" . $tag1 . "|" . $tag2 . "|" . $tag3 . ")\b/i";
var_dump($regex);

//loop through each product and throw matches to collection
foreach($arr as $product) {
    //var_dump($product);
    if(preg_match($regex,$product)) {
        array_push($collection,$product);
    }
}
var_dump($collection);
?>

Answer 4

Ive finally came up with a solution that worked. /^(?=.*?Tag1)(?=.*?Tag2)(?=.*?Tag3).*$/ works like a charm