/^(www.)?([a-z0-9]+)\..+\..*$/

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www.shannazalud.surpriseparties.com - 1
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donnadella.surpriseparties.com - 1
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surpriseparties.com - 0
Array
(
)
vikramdighe.surpriseparties.com - 1
Array
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asdf.vikramdighe.surpriseparties.com - 1
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asdf.surpriseparties.com - 1
Array
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)
asdf..surpriseparties.com - 1
Array
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    [1] => 
    [2] => asdf
)