PHP获得文件扩展名三法

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Z}8LLU0//方法一:
mZKGqx0function extend_1($file_name)PHPChina 开源社区门户*f ?:Q @KKV
{
mF7mk(FH7fk0$retval="";PHPChina 开源社区门户8X9a!X%Z&t&l)AwKh
$pt=strrpos($file_name, ".");PHPChina 开源社区门户7N.kI.lPZ^
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if ($pt) $retval=substr($file_name, $pt+1, strlen($file_name) - $pt);
Q cf\/N1G0return ($retval);PHPChina 开源社区门户c Q![$Jp(A tz5@0Bh
}

R)uK4cj0//方法二PHPChina 开源社区门户5zbw
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function extend_2($file_name)PHPChina 开源社区门户J ~GO/a.}
{
%G0^P'j(k2c^+iAv0$extend = pathinfo($file_name);
(_*Pf;eR0$extend = strtolower($extend["extension"]);
9}rd?5s)[0B0return $extend;PHPChina 开源社区门户 `*h*`J.KxY
}

Uu;TrY9d.g0//方法三
s wmj%_h0function extend_3($file_name)
:p#BC+Fb7f0{PHPChina 开源社区门户(W2e@I\Lk,]
$extend =explode("." , $file_name);PHPChina 开源社区门户 ]@*u'N)Y'EZ-q F
$va=count($extend)-1;
s?zoC'O.?#y0return $extend[$va];PHPChina 开源社区门户S)n(las6e6b
}
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