PHP数组(3)

例子 11-8. 填充数组

＜?php
// fill an array with all items from a directory
$handle = opendir('.');
while (false !== ($file = readdir($handle))) {
   $files[] = $file;
}
closedir($handle);
?＞
 

数组是有序的。你也可以使用不同的排序函数来改变顺序。更多信息参见数组函数库。您可以用 count() 函数来数出数组中元素的个数。

例子 11-9. 数组排序

＜?php
sort($files);
print_r($files);
?＞
 

因为数组中的值可以为任意值，也可是另一个数组。这样你可以产生递归或多维数组。

例子 11-10. 递归和多维数组

 array ( "a" => "orange",
                                       "b" => "banana",
                                       "c" => "apple"
                                     ),
                 "numbers" => array ( 1,
                                       2,
                                       3,
                                       4,
                                       5,
                                       6
                                     ),
                 "holes"  => array (      "first",
                                       5 => "second",
                                           "third"
                                     )
               );

// Some examples to address values in the array above
echo $fruits["holes"][5];    // prints "second"
echo $fruits["fruits"]["a"]; // prints "orange"
unset($fruits["holes"][0]);  // remove "first"

// Create a new multi-dimensional array
$juices["apple"]["green"] = "good";
?>
 

您需要注意数组的赋值总是会涉及到值的拷贝。您需要在复制数组时用指向符号（&）。

＜?php
$arr1 = array(2, 3);
$arr2 = $arr1;
$arr2[] = 4; // $arr2 is changed,
             // $arr1 is still array(2,3)

$arr3 = &$arr1;
$arr3[] = 4; // now $arr1 and $arr3 are the same
?＞