我可以通过数字索引访问关联数组吗？

问题描述：

I would like to know if it is possible to get the x-value position (ie 2nd) in a variable variable array reference.

the code below works for the 1st array but not the 2nd.

// WORKS FINE //
$my1stArray= array( 'red', 'green', 'blue');
$var_1st = 'my1stArray';

// for each lopp of var var works fine
echo " - my1stArray Values - <br>";
foreach ($$var_1st as $k => $v){
echo $k." : ".$v." <br>";
}
// direct access also works
echo "my1stArray 3rd value: ".${$var_1st}[2]."<br>";

// Not so good! //
$my2ndArray = array(
    'color' => '#ff0000',
    'face' => 'helvetica',
    'size' => '+5',
);
$var_2nd = 'my2ndArray';

// for each lopp of var_2nd works fine
echo "<br> - my2ndArray Values - <br>";
foreach ($$var_2nd as $k => $v){
echo $k." : ".$v." <br>";
}
/** try to access 2nd value in array with position **/
echo "my2ndArray 2rd value: ".${$var_2nd[1]}[0]."<br>";
echo "my2ndArray 2rd value: ".${$var_2nd}[1][0]."<br>";

我想知道是否有可能在变量变量中得到x值位置（即第2个）数组引用。 p>

下面的代码适用于第一个数组，但不适用于第二个数组。 p>

  // WORKS FINE // 
 $ my1stArray = array（'red'，'green'，'blue'）; 
 $ var_1st ='my1stArray'; \  n 
 //为var var的每个lopp工作fine 
echo“ -  my1stArray Values  - ＆lt; br＆gt;”; 
foreach（$ var_1st as $ k =＆gt; $ v）{
echo $ k。“：”  。$ v。“＆lt; br＆gt;”; 
} 
 //直接访问也有效
echo“my1stArray 3rd value：”。$ {$ var_1st} [2]。“＆lt; br＆gt;”; 
 \  n //不太好！  // 
 $ my2ndArray = array（
'color'=＆gt;'＃ff0000'，
'face'=＆gt;'helvetica'，
'size'=＆gt;'+ 5'，
）  ; 
 $ var_2nd ='my2ndArray'; 
 
 //为var_2nd的每个lopp工作正常
echo“＆lt; br＆gt;  -  my2ndArray值 - ＆lt; br＆gt;”; 
foreach（$$ var_2nd as $ k =  ＆gt; $ v）{
echo $ k。“：”。$ v。“＆lt; br＆gt;”; 
} 
 / **尝试访问位置为** / 
echo“my2ndArray 2rd的数组中的第二个值 值：“。$ {$ var_2nd [1]} [0]。”＆lt; br＆gt;“; 
echo”my2ndArray 2rd value：“。$ {$ var_2nd} [1] [0]。”＆lt; br＆gt;“  ; 
  code>  pre> 
  div>

答

Well, in the comments I said "no, you can't", but there is actually a way. Here is an example (without variable variables):

$my2ndArray = array(
    'color' => '#ff0000',
    'face' => 'helvetica',
    'size' => '+5',
);
$keys = array_keys($my2ndArray);
echo "my2ndArray 2nd value: " . $my2ndArray[$keys[1]]  . "<br>";

Doesn't look very nice, but should work. Not that if you ever sort the array, the key indexes will change.

Another way to do that would be using a counter and a loop as I mentioned in the comments. But that would be even uglier...

答

Your last example in your code is not working for the same reason that the following code does not work:

$a = array('akey'=>'a','bkey'=>'b');
echo $a[0];

The reason is the key is set to a string and must be accessed as such. To fix my example I would need to change it to:

$a = array('akey'=>'a','bkey'=>'b');
echo $a['akey'];

To fix your example you need to change your last echo so that it references the key as a string:

echo "my2ndArray 2rd value: ".${$var_2nd}['color']."<br>";

我可以通过数字索引访问关联数组吗？

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