How to verify the validity of a license plate number using regular expressions in PHP

As the number of vehicles continues to increase, the verification of license plate numbers has become a problem that must be solved. In PHP, you can easily verify the validity of license plate numbers using regular expressions. This article will introduce how to use regular expressions to verify the validity of license plate numbers.

1. The basic format of the license plate number

The license plate number is composed of Chinese characters, letters and numbers. Different regions have different formats. For example, the license plate number in Beijing is "Beijing A12345", the license plate number in Shanghai is "Shanghai A12345", and the license plate number in Hangzhou is "Zhejiang A12345", where "Beijing", "Shanghai" and "Zhejiang" are the abbreviations of the provinces. The following letters are the city code and the numbers are the serial number.

According to the national standard GB/T 8569-2017, the basic format of the license plate number is as follows:

Province abbreviation City code Trailer number Serial number

Among them, "Trailer number ” refers to the letter mark used to distinguish different types of vehicles, such as police cars, fire trucks, etc. The "serial number" is used to distinguish different vehicles of the same model.

2. The concept of regular expression

Regular expression is a language that describes string patterns and is used to match and locate strings that conform to certain rules. In PHP, regular expression matching of strings can be achieved using the preg_match() function.

The preg_match() function has three parameters, which are the regular expression, the string to be matched and an optional array variable. If the match is successful, 1 is returned, otherwise 0 is returned. If an array variable is provided, all matching results will be stored in the array.

3. Regular expression of license plate number

Since the license plate number formats are different in different regions, different regular expressions need to be written for different formats. Below are some common license plate number formats and corresponding regular expressions.

1. Beijing license plate number format

Beijing’s license plate number consists of one letter and 5 digits, of which the first digit cannot be 0.

The regular expression is: /^京[A-HJ-NP-Z]d{5}$/u

2. Shanghai license plate number format

Shanghai’s license plate number consists of one letter and 5 digits, of which the first digit cannot be 0.

The regular expression is: /^沪[A-HJ-NP-Z]d{5}$/u

3. Hangzhou license plate number format

The license plate number in Hangzhou consists of one letter and 5 digits, of which the first digit cannot be 0.

The regular expression is: /^Zhe [A-HJ-NP-Z]d{5}$/u

Among them, the u identifier matches in UTF-8 mode.

4. Use regular expressions to verify license plate numbers

In PHP, you can easily verify the validity of license plate numbers by using the preg_match() function combined with regular expressions. The following is a sample code:

$plate_number = '粤B12345'; // 车牌号码
$pattern = '/^粤[A-HJ-NP-Z]d{5}$/u'; // 正则表达式

if (preg_match($pattern, $plate_number)) {
    echo '车牌号码有效';
} else {
    echo '车牌号码无效';
}

In the above code, $plate_number is the license plate number to be verified, $pattern is the regular expression used to match the license plate number, use the preg_match() function to match, and based on The matching result outputs the verification result.

Conclusion

This article introduces how to use regular expressions to verify the validity of license plate numbers in PHP. Since the license plate number formats are different in different regions, corresponding regular expressions need to be written according to the actual situation. By using regular expressions to validate license plate numbers, you can improve the accuracy and reliability of your program. I hope this article can be helpful to everyone.

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