php array_shift vs在关联数组中取消设置

问题描述：

Hi what is the difference between array_shift and unset in associative array?

I understand how in a normal array, if you use array_shift, the key is still there and only the first value goes away but in associative array, I don't see any difference between array_shift and unset.

below is the code example:

    $a=array("a"=>"red","b"=>"green","c"=>"blue");
    $key=key($a);
    unset($a[$key]);
    print_r ($a);

    //result: Array ( [b] => green [c] => blue )

    $b=array("a"=>"red","b"=>"green","c"=>"blue");
    array_shift($b);
    print_r ($b);

    //result: Array ( [b] => green [c] => blue )

关联数组中array_shift和unset之间有什么区别？ p>

我理解在普通数组中，如果使用array_shift，键仍然存在，只有第一个值消失，但在关联数组中，我没有看到array_shift和unset之间有任何区别。 p>

下面是代码示例： p>

  $ a = array（“a”=＆gt;“red”，“b”=＆gt;“green”，“c  “=＆gt;”blue“）; 
 $ key = key（$ a）; 
 unset（$ a [$ key]）; 
 print_r（$ a）; 
 
 //结果：数组（  [b] =＆gt;绿色[c] =＆gt;蓝色）
 
 $ b =数组（“a”=＆gt;“红色”，“b”=＆gt;“绿色”，“c”=＆gt;  “blue”）; 
 array_shift（$ b）; 
 print_r（$ b）; 
 
 //结果：数组（[b] =＆gt;绿色[c] =＆gt;蓝色）
  代码>  pre> 
  div>

答

array_shift will return the head of your array (in this instance entry "a")

while unset will remove an element by its key, say unset($a['b']) will leave you with Array ( [a] => red [c] => blue )

php array_shift vs在关联数组中取消设置

相关推荐