用于验证字母数字字符串的 php 代码

php code to validate alphanumeric string

提问by jayant kumar

I want to validate alphanumeric string in form text box in php. It can contain numbers and special characters like '.' and '-' but the string should not contain only numbers and special characters. Please help with the code.

我想验证 php 表单文本框中的字母数字字符串。它可以包含数字和特殊字符，如“.” 和 '-' 但字符串不应只包含数字和特殊字符。请帮忙看代码。

回答by Ravinder Payal

Use ctype_alnumlike below:

使用ctype_alnum如下：

if(ctype_alnum($string)){
    echo "Yes, It's an alphanumeric string/text";
}
else{
    echo "No, It's not an alphanumeric string/text";
}

Read function specification on php.net

在php.net上阅读函数规范

回答by Sankar V

Try this

尝试这个

// Validate alphanumeric
if (preg_match('/^[a-zA-Z]+[a-zA-Z0-9._]+$/', $input)) {
    // Valid
} else {
    // Invalid
}

回答by Navneet Soni

Code:

代码：

if(preg_match('/[^a-z_\-0-9]/i', $string)) { echo "not valid string"; }if(preg_match('/[^a-z_\-0-9]/i', $string)) { echo "not valid string"; }

Explanation:

解释：

• [] => character class definition
• ^ => negate the class
• a-z => chars from 'a' to 'z'
• _ => underscore
• - => hyphen '-' (You need to escape it)
• 0-9 => numbers (from zero to nine)

• [] => 字符类定义
• ^ => 否定类
• az => 从 'a' 到 'z' 的字符
• _ => 下划线
• - => 连字符“-”（你需要转义它）
• 0-9 => 数字（从零到九）

The 'i' modifier at the end of the regex is for 'case-insensitive' if you don't put that you will need to add the upper case characters in the code before by doing A-Z

正则表达式末尾的“i”修饰符用于“不区分大小写”，如果您不添加，则需要在执行 AZ 之前在代码中添加大写字符

回答by rinchik

I'm sort of new to regex, but I would do it this way:

我对正则表达式有点陌生，但我会这样做：

preg_match('/^[\w.-]+$/', input)