gistfile1.txt

$result = preg_replace("/(?<=<row\\sr=\\\")[0-9]+(?=\\\">)|(?<=\\sr\\=\\\")([A-Z]+)([0-9]+)(?=\\\")/usx", "5", $searchText);

given.xml

<row r="4">
    <c r="A4" s="0" t="inlineStr">
        <is>
            <t>7</t>
        </is>
    </c>
    <c r="AZ4" s="0" t="inlineStr">
        <is>
            <t>No</t>
        </is>
    </c>
    <c r="AA7" s="3" t="n">
        <v>159900</v>
    </c>
    <c r="AZ7" s="4" t="n">
        <v>40867</v>
    </c>
</row>

<row r="40000009">
    <c r="A4" s="0" t="inlineStr">
        <is>
            <t>7</t>
        </is>
    </c>
    <c r="Z4" s="0" t="inlineStr">
        <is>
            <t>No</t>
        </is>
    </c>
    <c r="AA7" s="3" t="n">
        <v>159900</v>
    </c>
    <c r="AZ7" s="4" t="n">
        <v>40867</v>
    </c>
</row>