php 从数组中返回前 x 项
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Returning first x items from array
提问by O..
I want to return first 5 items from array. How can I do this?
我想从数组中返回前 5 个项目。我怎样才能做到这一点？
回答by knittl
array_slicereturns a slice of an array
array_slice返回一个数组的切片
$sliced_array = array_slice($array, 0, 5)
is the code you want in your case to return the first five elements
是您希望在您的案例中返回前五个元素的代码
回答by Andrejs Cainikovs
array_splice— Remove a portion of the array and replace it with something else:
array_splice— 移除数组的一部分并将其替换为其他内容：
$input = array(1, 2, 3, 4, 5, 6);
array_splice($input, 5); // $input is now array(1, 2, 3, 4, 5)
From PHP manual:
来自 PHP 手册：
array array_splice ( array &$input , int $offset [, int $length = 0 [, mixed $replacement]])
If length is omitted, removes everything from offset to the end of the array. If length is specified and is positive, then that many elements will be removed. If length is specified and is negative then the end of the removed portion will be that many elements from the end of the array. Tip: to remove everything from offset to the end of the array when replacement is also specified, use count($input) for length .
如果省略 length ，则删除从 offset 到数组末尾的所有内容。如果指定了长度并且是正数，那么将删除许多元素。如果指定了 length 并且为负数，则删除部分的末尾将是数组末尾的许多元素。提示：要在还指定替换时删除从偏移量到数组末尾的所有内容，请使用 count($input) for length 。
回答by Anax
If you just want to output the first 5 elements, you should write something like:
如果你只想输出前 5 个元素，你应该这样写：
<?php
if (!empty ( $an_array ) ) {
$min = min ( count ( $an_array ), 5 );
$i = 0;
foreach ($value in $an_array) {
echo $value;
$i++;
if ($i == $min) break;
}
}
?>
If you want to write a function which returns part of the array, you should use array_slice:
如果你想写一个返回数组一部分的函数，你应该使用array_slice：
<?php
function GetElements( $an_array, $elements ) {
return array_slice( $an_array, 0, $elements );
}
?>
回答by Cesar
You can use array_slice function, but do you will use another values? or only the first 5? because if you will use only the first 5 you can use the LIMIT on SQL.
您可以使用 array_slice 函数，但是您会使用其他值吗？还是只有前5个？因为如果您只使用前 5 个，则可以在 SQL 上使用 LIMIT。
回答by Jason
A more object oriented way would be to provide a range to the #[] method. For instance:
一种更面向对象的方法是为 #[] 方法提供一个范围。例如：
Say you want the first 3 items from an array.
假设您想要数组中的前 3 个项目。
numbers = [1,2,3,4,5,6]
数字 = [1,2,3,4,5,6]
numbers[0..2] # => [1,2,3]
数字[0..2] # => [1,2,3]
Say you want the first x items from an array.
假设您想要数组中的前 x 项。
numbers[0..x-1]
数字[0..x-1]
The great thing about this method is if you ask for more items than the array has, it simply returns the entire array.
这种方法的好处在于，如果您要求的项目比数组多，它只会返回整个数组。
numbers[0..100] # => [1,2,3,4,5,6]
数字[0..100] # => [1,2,3,4,5,6]
