


With the widespread use of Web applications, security issues have attracted more and more attention. One of the important security measures is to filter and verify the data entered by the user. PHP provides a series of filter functions, among which there is a very practical function - filter_var_array(). This function can filter multiple data at the same time and is a very efficient and convenient tool. This article will introduce the usage of this function in detail and provide you with specific code examples.
- Basic usage of filter_var_array() function
filter_var_array() function is used to filter multiple data. Its basic syntax is as follows:
filter_var_array ( array $data [, mixed $definition [, bool $add_empty = true ]] ) : array
Among them, $data represents the data to be filtered and must be an associative array. $definition represents the filtering rule, which can be an array or a constant. $add_empty indicates whether to include the empty string.
This function returns the filtered data, which is also an associative array.
- Use the filter_var_array() function to filter the data entered by the user
Now suppose we have a form that contains three input boxes: username, password and email address. We need to filter and verify the data in these three input boxes to ensure that the data is in the correct format before storing it in the database. The following is the code that uses the filter_var_array() function to accomplish this task:
<?php //从表单中获取数据 $username = $_POST['username']; $password = $_POST['password']; $email = $_POST['email']; //定义过滤规则 $definition = array( 'username' => FILTER_SANITIZE_STRING, 'password' => FILTER_SANITIZE_STRING, 'email' => FILTER_VALIDATE_EMAIL ); //使用filter_var_array()函数过滤数据 $data = filter_var_array(array( 'username' => $username, 'password' => $password, 'email' => $email ), $definition); //判断用户输入是否合法 if($data['username'] && $data['password'] && $data['email']){ //存储到数据库中 //... }else{ //提示用户输入不合法 //... } ?>
In the above code, three variables $username, $password and $email are first obtained from the form. Then we defined a $definition array, in which the filtering rule for 'username' and 'password' is FILTER_SANITIZE_STRING (removing labels and special characters), and the filtering rule for 'email' is FILTER_VALIDATE_EMAIL (checking whether it is a legal email address).
Next, we pass the three obtained variables and the defined $definition array to the filter_var_array() function, and save the return result in the $data array. Finally, we determine whether the three elements in the $data array are not empty. If they are not empty, the data can be stored in the database. Otherwise, the user will be prompted that the input is illegal.
Through the above code examples, we can see that the filter_var_array() function is efficient and convenient, and can easily filter and verify multiple data.
- Constants of filter_var_array() function
In the above example we used two filter constants: FILTER_SANITIZE_STRING and FILTER_VALIDATE_EMAIL, these two constants are defined in the filter_var() function , or can be used directly in the filter_var_array() function. However, in addition to these two constants, the filter_var_array() function has many other constants that can be used. The following are some commonly used filter constants:
- FILTER_VALIDATE_BOOLEAN: Check whether it is a Boolean type
- FILTER_VALIDATE_INT: Check whether it is an integer
- FILTER_VALIDATE_FLOAT: Check whether it is a floating point number
- FILTER_VALIDATE_REGEXP: Check whether it matches the specified regular expression
- FILTER_VALIDATE_URL: Check whether it is a URL address
- FILTER_SANITIZE_SPECIAL_CHARS: Escape special characters into HTML entities
- FILTER_SANITIZE_NUMBER_INT : Remove non-numeric characters from a string
- Summary
In this article, we introduce the usage of PHP's filter_var_array() function in detail and give specific code examples. Through the demonstration of actual cases, readers can clearly understand how to use this function to filter and verify user-entered data to ensure the security of web applications.
The above is the detailed content of Use PHP's filter_var_array() function to filter data entered by multiple users. For more information, please follow other related articles on the PHP Chinese website!

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

SublimeText3 Linux new version
SublimeText3 Linux latest version

Notepad++7.3.1
Easy-to-use and free code editor

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

Dreamweaver CS6
Visual web development tools
