从数组中删除重复项(数组unic by key)

Question

Array
(
    [0] => Array
        (
            [file] => /var/websites/example.com/assets/images/200px/1419050406e6648e1c766551a0ffc91380fd6ff3406002011-10-233750.jpg
            [md5] => 42479bee7a304d2318250de2ef1962a9
            [url] => http://example.com/assets/images/200px/1419050406e6648e1c766551a0ffc91380fd6ff3406002011-10-233750.jpg
        )

    [1] => Array
        (
            [file] => /var/websites/example.com/assets/images/200px/21277792606e6648e1c766551a0ffc91380fd6ff3406002011-10-233750.jpg
            [md5] => 42479bee7a304d2318250de2ef1962a9
            [url] => http://example.com/assets/images/200px/21277792606e6648e1c766551a0ffc91380fd6ff3406002011-10-233750.jpg
        )
)

如何从上面的数组中删除md5密钥重复项？

Answer 1

<?php
$data = array(
  array(
    'md5' => 'alpha',
    'some' => 'value',
  ),
  array(
    'md5' => 'alpha',
    'some' => 'other value',
  ),
  array(
    'md5' => 'bravo',
    'some' => 'third value',
  ),
);
// walk input array
$_data = array();
foreach ($data as $v) {
  if (isset($_data[$v['md5']])) {
    // found duplicate
    continue;
  }
  // remember unique item
  $_data[$v['md5']] = $v;
}
// if you need a zero-based array, otheriwse work with $_data
$data = array_values($_data);

Answer 2

PHP已经具有从数组中删除重复元素的功能.但不幸的是,array_unique它只支持基于字符串的比较:

注意:当且仅当两个元素被认为是相等的(string) $elem1 === (string) $elem2.用文字表示:当字符串表示相同时.将使用第一个元素.

问题是任何变成字符串的数组都等于任何其他数组:

数组总是转换为字符串" Array"; [...]

但是你可以使用数组键的唯一性来解决这个问题:

$index = array();
foreach ($arr as $key => $item) {
    if (isset($index[$item['md5']])) {
        unset($item[$key]);
    }
    $index[$item['md5']] = TRUE;
}

Answer 3

这是我的帮助之后的最终功能....希望它能帮助将来的某个人......

    $data = array(
          array(
            'md5' => 'alpha',
            'some' => 'value',
          ),
          array(
            'md5' => 'alpha',
            'some' => 'other value',
          ),
          array(
            'md5' => 'bravo',
            'some' => 'third value',
          ),
        );
        // walk input array


        function remove_duplicateKeys($key,$data){

        $_data = array();

        foreach ($data as $v) {
          if (isset($_data[$v[$key]])) {
            // found duplicate
            continue;
          }
          // remember unique item
          $_data[$v[$key]] = $v;
        }
        // if you need a zero-based array
        // otherwise work with $_data
        $data = array_values($_data);
        return $data;
        }

$my_array = remove_duplicateKeys("md5",$data);