有个二维数组：
$arr = array( array('num'=>5,'period'=>3), array('num'=>10,'period'=>3), array('num'=>15,'period'=>9));

对period相同的值的数组，对num求和，怎么处理变成：
$arr = array( array('num'=>15,'period'=>3), array('num'=>15,'period'=>9));

回复内容： 有个二维数组：
$arr = array( array('num'=>5,'period'=>3), array('num'=>10,'period'=>3), array('num'=>15,'period'=>9));

对period相同的值的数组，对num求和，怎么处理变成：
$arr = array( array('num'=>15,'period'=>3), array('num'=>15,'period'=>9));

把 @mot 的答案补完优雅一下：
$arr = array( array('num'=>5,'period'=>3), array('num'=>10,'period'=>3), array('num'=>15,'period'=>9));$temp = array();foreach($arr as $item) { list($n, $p) = array_values($item); $temp[$p] = array_key_exists($p, $temp) ? $temp[$p]+$n : $n;}$arr = array();foreach($temp as $p => $n) $arr[] = array('num'=>$n, 'period'=>$p);print_r($arr);
$tmp = array();foreach( $arr as $one){ if( $tmp[$one['period']] ) $tmp[$one['period']] = $tmp[$one['period']] + $one['num']; else $tmp[$one['period']] = $one['num'];}$arr = array();foreach ( $tmp as $key => $value ) $arr[] = array( 'num' => $value , 'period' => $key );
function merge($items){
$data = array();
foreach ($items as $v) {
$p = $v['period'];
if(array_key_exists($p, $data)){
$data[$p]['num'] += $v['num'];
}else{
$data[$p] = array('num'=>$v['num'],'period'=>['period']);
}
}
return $data = array_values($data);
}
$arr1 = array( array('num'=>5,'period'=>3), array('num'=>10,'period'=>3), array('num'=>15,'period'=>9));$arr2 = array();foreach($arr1 as $k1 => $v1) { if(empty($arr2)) { $arr2[] = $v1; } else { foreach ($arr2 as &$v2) { if($v1['period'] == $v2['period']) { $v2['num'] += $v1['num']; } else { $arr2[] = $v1; } } }}
5, 'period'=>3), array('num'=>10,'period'=>3), array('num'=>15,'period'=>9));$result = array();$arr = array_reduce($arr, function($prev, $val) use (&$result) { if (empty($prev)) { return $val; } if (isset($prev['period']) && $prev['period'] === $val['period']) { $prev['num'] += $val['num']; } else { $result[] = $val; $prev = array(); } empty($prev) || $result[] = $prev; return $prev;}, array());print_r($result);
$arr = array( array('num'=>5,'period'=>3), array('num'=>10,'period'=>3), array('num'=>15,'period'=>9));$keyvalue = [];array_filter( $arr, function ($item) use (&$keyvalue) { if (array_key_exists($item['period'], $keyvalue)) { $keyvalue[$item['period']] = [ 'period' => $item['period'], 'num' => $item['num'] + $keyvalue[$item['period']]['num'] ]; return false; } else { $keyvalue[$item['period']] = [ 'period' => $item['period'], 'num' => $item['num'] ]; return true; } });var_dump(array_values($keyvalue));
感觉这样可能简单点。