Remove all characters except az AZ 0-9 or null via PHP regex

In "Delete non-numeric characters except commas and dots through PHP regular expressions" we will introduce to you how to use regular expressions to delete non-numeric characters except commas and dots. I believe you already have some understanding of the use of regular expressions, so today I will continue to bring you examples of using PHP regular expressions~

As the title states, in this article we will delete strings through regular expressions All characters except az AZ 0-9 or " ".

First give you an example string: abcde$ddfd @abcd )der]

You can first write a method locally to delete the string. All characters except az AZ 0-9 or " ".

The following is my method:

<?php
$string = &#39;abcde$ddfd @abcd )der]&#39;;
echo &#39;原始字符串 : &#39;.$string.&#39;<br>&#39;;
$newstr = preg_replace("/[^A-Za-z0-9 ]/", &#39;&#39;, $string);
echo &#39;新字符串 : &#39;.$newstr."<br>";

Let’s run the result directly, as shown in the figure below:

You can see This result is what our title requires!

Isn’t it so easy!

The use of regular expressions in PHP is nothing more than the use of the preg_replace function and the mastery of regular expression matching rules.

About preg_replaceThe syntax is briefly introduced here:

mixed preg_replace ( mixed $pattern , mixed $replacement , mixed $subject [, int $limit = -1 [, int &$count ]] )

means that you can search for the part of the subject that matches the pattern and replace it with replacement.

Attachment:

Introduction to the concept of regular expressions:

Regular expression is a logical formula for string operations, which uses some specific characters defined in advance. and the combination of these specific characters to form a "rule string". This "rule string" is used to express a filtering logic for strings.

Finally, I would like to recommend "Regular Expression Manual" to everyone. I believe that as long as you read this tutorial carefully and make certain references when applying it, mastering regular expressions will not be a problem.

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