Php 将大文本拆分为数量可变的部分

我需要这样的东西：

$x = 4;
$story = "BUT I MUST EXPLAIN TO YOU HOW ALL THIS MISTAKEN IDEA OF DENOUNCING PLEASURE AND PRAISING PAIN WAS BORN AND I WILL GIVE YOU A COMPLETE ACCOUNT OF THE SYSTEM AND EXPOUND THE ACTUAL TEACHINGS OF THE GREAT EXPLORER";

例如，如果

$x==4

每个元素将包含四个单词：

但我必须解释一下
对你来说怎么样
etc

如果

$x==5

每个元素将包含五个单词：

但我必须向你解释
你怎么弄错了
etc

---

有什么想法吗？

您可以使用

array\u chunk（）

来执行此操作：

$arr = explode(' 'nth($x), $story);

---

您已经尝试了什么？一种方法是计算单词之间的空格，并在$x-1空格后拆分字符串。但这只是一个粗略的想法。
<?php
    $x = 4;
    $story = "BUT I MUST EXPLAIN TO YOU HOW ALL THIS MISTAKEN IDEA OF DENOUNCING PLEASURE AND PRAISING PAIN WAS BORN AND I WILL GIVE YOU A COMPLETE ACCOUNT OF THE SYSTEM AND EXPOUND THE ACTUAL TEACHINGS OF THE GREAT EXPLORER";

    # we do a normal explode to get it into an array
    $arr = explode(' ', $story);
    # break into arrays divided by $x
    echo '<pre>'. print_r(array_chunk($arr, $x), 1) .'</pre>';

<?php
$story = "BUT I MUST EXPLAIN TO YOU HOW ALL THIS MISTAKEN IDEA OF DENOUNCING PLEASURE AND PRAISING PAIN WAS BORN AND I WILL GIVE YOU A COMPLETE ACCOUNT OF THE SYSTEM AND EXPOUND THE ACTUAL TEACHINGS OF THE GREAT EXPLORER";

foreach(
    array_chunk(
        str_word_count($story, 1),
        4 // Your chunk size.
    ) as $group
)
    echo implode(' ', $group), "\n";

BUT I MUST EXPLAIN
TO YOU HOW ALL
THIS MISTAKEN IDEA OF
DENOUNCING PLEASURE AND PRAISING
PAIN WAS BORN AND
I WILL GIVE YOU
A COMPLETE ACCOUNT OF
THE SYSTEM AND EXPOUND
THE ACTUAL TEACHINGS OF
THE GREAT EXPLORER