正则表达式删除第一次出现和第一次出现

Question

Hi search the regex version of this code :

$val = '<label for="A" >A</label><label for="B"><div>X</div></label><label for="C"><div>Y</div></label>';           
            $firstLabelPos = strpos($val,'<label for="B">');
            $sideB = substr($val,$firstLabelPos + strlen('<label for="B">') );
            $firstLabelPos2 = strpos($sideB,'</label>');
            $result =   substr($val,0,$firstLabelPos-1)
                        .substr($sideB,0,$firstLabelPos2)
                        .substr($sideB,$firstLabelPos2+strlen('</label>'));


result : <label for="A" >A</label<div>X</div><label for="C"><div>Y</div></label>

The code find <label for="B"> and the closest </label>. Make a new string with what was before, inside and after.

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Its how to remove the label around a div by the "for" attribute. Or you can say, how to remove the first occurrence of <label for="B"> and the closest occurrence of </label>.

If you can also make sur that we dont touch what is inside the <label...</label> (could be another label). That will be appreciate for further practice.