如何获取数组的第一个元素？

Question

我有一个数组：

array( 4 => 'apple', 7 => 'orange', 13 => 'plum' )

我想得到这个数组的第一个元素。结果预计是： string apple

一个问题是：它不能通过引用传递，所以数组移位不是一个好的解决方案。

可以怎么做？

Answer 1

Original answer, but costly (O(n)):

array_shift(array_values($array));

In O(1):

array_pop(array_reverse($array));

Edited with suggestions from comments for other use cases etc...

If modifying (in the sense of resetting array pointers) of $array is not a problem, you might use:

reset($array);

This should be theoretically more efficient, if a array "copy" is needed:

array_shift(array_slice($array, 0, 1)); 

With PHP 5.4+ (but might cause an index error if empty):

array_values($array)[0];