How to escape specified characters in php

php method to escape specified characters: 1. Create a PHP sample file; 2. Define the string; 3. Escape the string through the "addslashes($str);" method.

The operating environment of this article: Windows 7 system, PHP version 7.1, DELL G3 computer

How to escape specified characters in php?

First of all, you can briefly understand what an escape character is? What is the use?

The escape character is a special character constant. The escape character starts with a backslash "\" and is followed by one or more characters. Escape characters have specific meanings that are different from the original meaning of the characters, so they are called "escape" characters.

Uses of escape characters:

1: Convert ordinary characters to special uses, such as back key, enter key, etc.

2: Used to convert special meaning characters back to their original meaning.

3: Before data is written to the database, escape characters (functions) will be used to escape some sensitive characters. Avoid website injection attacks.

Then during the PHP development project, we may encounter operations that require escaping a large amount of data.

Below we will introduce how to escape and restore strings in PHP through simple code examples.

1. Examples of using functions to escape strings:

<?php
$str = "[&#39;name&#39;=>&#39;张三&#39;,&#39;age&#39;=>19]";
echo $str . "<br>";
//对字符串进行转义
$a = addslashes($str);
//输出转义后的字符串
echo $a . "<br>";

addslashes function: Use backslashes to quote strings.

The parameters represent the character data to be escaped. The return value is the escaped character.

In the above code, we define an array variable $str and use double single quotes to express it, and then use the addslashes function in PHP to escape. We need to note here that we cannot use four double quotes, because then the system will not be able to parse the beginning and end of the string, and an error will occur.

Then access it through the browser, and the result of escaping the string data is as shown below:

2. Example of using the function to restore the string:

<?php
$str = "[&#39;name&#39;=>&#39;张三&#39;,&#39;age&#39;=>19]";
echo $str . "<br>";
//对字符串进行转义
$a = addslashes($str);
//输出转义后的字符串
echo $a . "<br>";
//对转义后的字符串进行还原
$b = stripslashes($a);
//输出还原后的字符串
echo $b . "
";

stripslashes function: Backquote a quoted string.

The return value is a string without escaped backslashes (\' is converted to ', etc.). Double backslashes (\\) are converted to single backslashes (\).

Here we mainly use the stripslashes function to restore the escaped string.

The results of accessing through the browser are as follows:

Recommended learning: "PHP Video Tutorial"

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