$re = '/\<span\sclass\=\"js_value\stab-weather__value_l\"\>\s*+([+-]\d++)\s*+\<span\sclass\=\"tab-weather__value_m\"\>\s*+([.,]\d++)(?:\s*+\<\/span\>){2}/m';
$str = '<span class="js_value tab-weather__value_l">
+6<span class="tab-weather__value_m">,2</span></span>
<span class="js_value tab-weather__value_l">
-12<span class="tab-weather__value_m">.45</span></span>
<span class="js_value tab-weather__value_l">
+0<span class="tab-weather__value_m">,1</span></span>';
$subst = "$1$2";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php