How to get the first n elements of an array in PHP

In the previous article "How to find the first non-repeating character in a given string through PHP", I introduced how to find the first non-repeating character in a given string through PHP. Non-repeating characters. Interested friends can learn about it~

So this article will introduce to you how to get the array of the first n elements. What does it mean?

Let's take a look at the specific problem description: How to write a PHP program to get an array in which n elements are removed from the beginning of the given array.

It doesn’t matter if you don’t understand it yet, let’s look at the code directly:

The PHP code is as follows:

<?php
function take($items, $n = 1)
{
    return array_slice($items, 0, $n);
}
var_dump(take([1, 2, 3], 1));

var_dump(take([1, 2, 3, 4, 5], 2));

The result of printing the obtained array is:

array (size=1)
  0 => int 1
array (size=2)
  0 => int 1
  1 => int 2

Note:

PHP array_slice()The function takes out a value in the array according to the conditions and returns it; the return value is the selection in the returned array fixed part. (If the array has string keys, the returned array will preserve the key names.)

array_slice()The syntax of the function is "array_slice(array,start,length,preserve )";

parameters respectively represent:

array必需，规定数组。
start必需，数值，规定取出元素的开始位置。 0 = 第一个元素。
---如果该值设置为正数，则从前往后开始取。
---如果该值设置为负数，则从后向前取 start 绝对值。 -2 意味着从数组的倒数第二个元素开始。
length可选，数值，规定被返回数组的长度。
---如果该值设置为整数，则返回该数量的元素。
---如果该值设置为负数，则函数将在举例数组末端这么远的地方终止取出。
---如果该值未设置，则返回从 start 参数设置的位置开始直到数组末端的所有元素。
preserve可选，规定函数是保留键名还是重置键名。可能的值：
---true - 保留键名
---false - 默认。重置键名

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