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PHP code:

Array ( [0] => hdd1 [1] => hda [2] => hda1 [3] => hda2 [4] => hda3 [5] => hdd [6]=>...)


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PHP code:

Array ( [0] => hdd [1] => hda [2] => ...)


Çë¸÷λ´óÅ£°ïÏÂ棬ллÁË

---

PHP code:
$arr1 = Array ( [0] => hdd1 [1] => hda [2] => hda1 [3] => hda2 [4] => hda3 [5] => hdd [6]=>...) ;
$arr2 = array();
foreach($arr1 as $item){
$str3 = substr($item,0,3);
if(!in_array($str3,$arr2))
$arr2[] = $str3;
}
print_r($arr2);

---

ÆæÒìµÄд·¨
$ar = array('hdd1', 'hda', 'hda1', 'hda2', 'hda3', 'hdd');

function foo($v) {
  return substr($v, 0, 3);
}

$ar = array_slice(array_flip(array_flip(array_map('foo', $ar))), 0); 
print_r($ar);

---

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PHP code:

Array(
['hdd'] => array(
[0] => 'hdd1'
)
['hda'] => array(
[0] =&