問題描述

背景: Trevor 正在使用標(biāo)準(zhǔn)算法的 PHP 實(shí)現(xiàn):采用一組主要的默認(rèn)名稱-值對(duì)，并更新這些名稱-值對(duì)，但僅限于那些名稱-值實(shí)際存在有效更新值的對(duì).

Background: Trevor is working with a PHP implementation of a standard algorithm: take a main set of default name-value pairs, and update those name-value pairs, but only for those name-value pairs where a valid update value actually exists.

問題:默認(rèn)情況下，PHP array_merge 是這樣工作的......它會(huì)用一個(gè)空值覆蓋一個(gè)非空值.

Problem: by default, PHP array_merge works like this ... it will overwrite a non-blank value with a blank value.

$aamain   =   Array('firstname'=>'peter','age'=>'32','nation'=>'');
$update   =   Array('firstname' => '','lastname' => 'griffin', age =>'33','nation'=>'usa');

print_r(array_merge($aamain,$update));    
/*
Array
(
    [firstname] =>           // <-- update set this to blank, NOT COOL!
    [age] => 33              // <-- update set this to 33, thats cool
    [lastname] => griffin    // <-- update added this key-value pair, thats cool
    [nation] => usa          // <-- update filled in a blank, thats cool.
)
*/

問題:在空值永遠(yuǎn)不會(huì)覆蓋現(xiàn)有值的情況下，執(zhí)行 array_merge 的最少代碼行方式是什么?

Question: What's the fewest-lines-of-code way to do array_merge where blank values never overwrite already-existing values?

print_r(array_coolmerge($aamain,$update));    
/*
Array
(
    [firstname] => peter  // <-- don't blank out a value if one already exists!
    [age] => 33
    [lastname] => griffin
    [nation] => usa

)
*/

更新: 2016-06-17T11:51:54 更新了問題，澄清了上下文和變量重命名.

UPDATE: 2016-06-17T11:51:54 the question was updated with clarifying context and rename of variables.

推薦答案

array_replace_recursive($array, $array2);

這就是解決方案.

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