PHP Algorithm Exercise 4: Multiply the corresponding elements of two given lists

This article continues to introduce the algorithm exercise series to you. In the previous article "PHP Algorithm Exercise 3: Exchange the first and last characters in the string", I introduced to you how to exchange the characters in the string. The first and last characters, interested friends can learn about it~

Now I will ask you a question: "How to write a PHP program to multiply the corresponding elements of two given lists" ?

What does it mean?

As shown in the picture below, just multiply the data corresponding to the two rows!

Okay, let’s go straight to the code:

The PHP code is as follows:

<?php

function multiply_two_lists($x, $y)
{
    $a = explode(&#39; &#39;,trim($x));
    $b = explode(&#39; &#39;,trim($y));
    foreach($a as $key=>$value){
        $output[$key] = $a[$key]*$b[$key];
    }
    return implode(&#39; &#39;,$output);
}
echo multiply_two_lists(("10 12 3"), ("1 3 3"))."<br>";

The output result is

In the above example, we gave two columns of data, namely 10, 12, 3 and 1, 3, 3.

Then multiply the corresponding elements of the two given lists, that is, find 10*1, 12*3, 3*3.

Obviously, the results of multiplication are 10, 36, and 9 respectively.

Here are 2 functions that you need to know about:

trim() Function: remove blank characters or other predefined characters on both sides of the string .

→Attached related functions: ltrim() removes blank characters or other predefined characters on the left side of the string. rtrim() removes whitespace characters or other predefined characters from the right side of a string.

explode()Function: Break up the string into an array.

The syntax is "explode(separator,string,limit)", and the return value is an array of returned strings.

→Note: The "separator" parameter cannot be an empty string. This function is binary safe.

I won’t introduce much about the foreach loop here. You can read the article "Usage of foreach in PHP".

Finally, I would like to recommend the latest and most comprehensive "PHP Video Tutorial"~ Come and learn!

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