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php数组对数组元素去重

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Release: 2016-06-13 09:56:40
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最简单的办法利用php自带的函数用array_flip实现去重效果,另一个方法是使用php的array_flip函数来间接的实现去重效果

array_flip是反转数组键和值的函数,他有个特性就是如果数组中有二个值是一样的,那么反转后会保留最后一个键和

值.利用这个特性我们用他来间接的实现数组的去重.

 代码如下 复制代码

$arr = array("a"=>"a1","b"=>'b1',"c"=>"a2","d"=>"a1");
$arr1 = array_flip($arr);
print_r($arr1);//先反转一次,去掉重复值,输出Array ( [a1] => d [b1] => b [a2] => c )
$arr2 = array_flip($arr);
print_r($arr2);//再反转回来,得到去重后的数组,输出Array ( [a1] => d [b1] => b [a2] => c )
$arr3 = array_unique($arr);
print_r($arr3);//利用php的array_unique函数去重,输出Array ( [a] => a1 [b] => b1 [c] => a2 )
?>

用户自定义函数操作

 代码如下 复制代码

function assoc_unique($arr, $key) {
 $tmp_arr = array();
 foreach($arr as $k => $v) {
  if(in_array($v[$key], $tmp_arr)) {
   unset($arr[$k]);
  } else {
   $tmp_arr[] = $v[$key];
  }
 }
 sort($arr);
 return $arr;
}

$aa = array(
 array('id' => 123, 'name' => '淡淡清香弥漫世界'),
 array('id' => 123, 'name' => '螃蟹'),
 array('id' => 124, 'name' => '前端开发者'),
 array('id' => 125, 'name' => '螃蟹'),
 array('id' => 126, 'name' => 'HTML5研究者')
);
$key = 'name';
assoc_unique(&$aa, $key);
print_r($aa);
?>

source:php.cn
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