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<?php $var = array( '#tag', 'text #tag text', 'text #tag', 'text#tag', ); $res = preg_replace('/(?<=\s)#\S{1,24}+/u', '<$0>' , $var); print_r($res); echo preg_replace('/(?<=\s)#\S{1,24}+/u', '<$0>' , '#111 тапинамбур#222 #333 #444');
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Array ( [0] => #tag [1] => text <#tag> text [2] => text <#tag> [3] => text#tag ) #111 тапинамбур#222 <#333> <#444>

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