某些索引后停止爆炸

Question

如何在某个索引后停止爆炸功能.例如

    <?php
        $test="The novel Prognosis Negative by Art Vandelay expresses protest against many different things. The story covers a great deal of time and takes the reader through many different places and events, as the author uses several different techniques to really make the reader think. By using a certain type of narrative structure, Vandelay is able to grab the reader’s attention and make the piece much more effective and meaningful, showing how everything happened";

    $result=explode(" ",$test);
    print_r($result);
?>

如果只想使用前10个元素怎么办($ result [10])如果填充了10个元素,怎么能停止爆炸功能呢？

一种方法是先将字符串修剪到前10个空格("")

有没有其他方法,我不想在限制后的任何地方存储剩余的元素(使用正限制参数完成)？

Answer 1

那个函数的第三个参数是什么？

array explode(string $ delimiter,string $ string [,int $ limit])

看看$limit参数.

手册:http://php.net/manual/en/function.explode.php

手册中的一个例子:

<?php
$str = 'one|two|three|four';

// positive limit
print_r(explode('|', $str, 2));

// negative limit (since PHP 5.1)
print_r(explode('|', $str, -1));
?>

The above example will output:

Array ( [0] => one [1] => two|three|four ) Array ( [0] => one [1] => two [2] => three )

In your case:

print_r(explode(" " , $test , 10));

According to the php manual , when you're using the limit parameter:

If limit is set and positive, the returned array will contain a maximum of limit elements with the last element containing the rest of string.

Therefore , you need to get rid of the last element in the array. You can do it easily with array_pop (http://php.net/manual/en/function.array-pop.php).

$result = explode(" " , $test , 10);
array_pop($result);