php 获取数组的前 N 个元素？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/3720096/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Get the first N elements of an array?
提问by GSto
What is the best way to accomplish this?
实现这一目标的最佳方法是什么？
回答by corbacho
Use array_slice()
使用array_slice()
This is an example from the PHP manual: array_slice
这是PHP 手册中的一个示例：array_slice
$input = array("a", "b", "c", "d", "e");
$output = array_slice($input, 0, 3); // returns "a", "b", and "c"
There is only a small issue
只有一个小问题
If the array indices are meaningful to you, remember that array_slicewill reset and reorder the numericarray indices. You need the preserve_keysflag set to trueto avoid this. (4th parameter, available since 5.0.2).
如果数组索引对您有意义，请记住这array_slice将重置并重新排序数字数组索引。您需要设置preserve_keys标志true来避免这种情况。（第四个参数，从 5.0.2 开始可用）。
Example:
例子：
$output = array_slice($input, 2, 3, true);
Output:
输出：
array([3]=>'c', [4]=>'d', [5]=>'e');
回答by codaddict
回答by Fanis Hatzidakis
In the current order? I'd say array_slice(). Since it's a built in function it will be faster than looping through the array while keeping track of an incrementing index until N.
按当前顺序？我会说array_slice()。因为它是一个内置函数，所以它比循环遍历数组要快，同时跟踪一个递增的索引直到 N。
回答by Star
array_slice()is best thing to try, following are the examples:
array_slice()是最好的尝试，以下是示例：
<?php
$input = array("a", "b", "c", "d", "e");
$output = array_slice($input, 2); // returns "c", "d", and "e"
$output = array_slice($input, -2, 1); // returns "d"
$output = array_slice($input, 0, 3); // returns "a", "b", and "c"
// note the differences in the array keys
print_r(array_slice($input, 2, -1));
print_r(array_slice($input, 2, -1, true));
?>
回答by Alon Gouldman
if you want to get the first N elements and alsoremove it from the array, you can use array_splice()(note the 'p' in "splice"):
如果您想获取前 N 个元素并将其从数组中删除，您可以使用array_splice()（注意“拼接”中的“p”）：
http://docs.php.net/manual/da/function.array-splice.php
http://docs.php.net/manual/da/function.array-splice.php
use it like so: $array_without_n_elements = array_splice($old_array, 0, N)
像这样使用它： $array_without_n_elements = array_splice($old_array, 0, N)
