PHP regular expression practice: matching ID number

In daily development, there are many scenarios where ID card numbers need to be matched. The ID number is a fixed format, but each province has slightly different rules, so a specific regular expression is needed to match.

PHP is a widely used programming language. It provides built-in regular expression functions and classes that can easily match ID numbers. This article will introduce how to use PHP regular expressions to match ID card numbers.

1. ID card number format

The ID number consists of 18 digits and a check code, where the check code may be numbers or the letter X. The first 17 digits represent the address code, date of birth code and sequence code, and the last digit is the check code used to verify the validity of the ID number.

The format of the ID number is as follows:

① Address code. A 6-digit number indicating the administrative division code of the place of household registration.

② Date of birth code. An 8-digit number indicating the date, month, and day of birth of the ID card holder.

③ Sequence code. A 3-digit number, indicating that it is unique under the same address code and date of birth code.

④ Verification code. 1 digit or letter, used to verify the validity of the ID number.

Because the administrative division codes of each province are different, different regular expressions are needed to match the ID number. Let's walk through how to write regular expressions to match ID numbers.

2. Address code matching

The address code is the first 6 digits of the ID number and is used to indicate the administrative division code of the place of household registration. Because the administrative division codes of each province are different, different regular expressions need to be written to match the address codes.

Take Beijing as an example. The address code of Beijing is 110000. The regular expression is as follows:

$pattern = '/^110000/';

Among them, ^ represents the beginning of the matching string, and 110000 represents the address code that needs to be matched.

The regular expressions of other provinces can be modified accordingly according to the administrative division code.

3. Date of birth code matching

The date of birth code is the 7th to 14th digits of the ID card number, used to indicate the year, month and day of birth of the ID card holder . The format of the date of birth code is yyyyMMdd, where yyyy represents the year of birth, MM represents the month of birth, and dd represents the day of birth.

The regular expression of date of birth code is as follows:

$pattern = '/^[1-9]d{5}(19|20)d{2}(0[1-9]|1[012])(0[1-9]|[12][0-9]|3[01])d{3}[0-9Xx]$/';

Among them, [1-9]d{5} represents the first 6 digits of the address code, and (19|20)d{2} represents The year of birth is from 1900 to 2099, (0[1-9]|1[012]) means the month of birth is from 01 to December, (0[1-9]|12|3[01]) means the day of birth is 01 Until the 31st, d{3} represents the sequence code, [0-9Xx] represents the check code (can be a number or letter X).

4. Complete regular expression

By combining the regular expression of the address code and date of birth code, you can get the complete matching rule for the ID number:

$pattern = '/^110000(19|20)d{2}(0[1-9]|1[012])(0[1-9]|[12][0-9]|3[01])d{3}[0-9Xx]$/';

This regular expression can match the ID card number of Beijing City, and the regular expressions of other provinces can be modified according to the corresponding administrative division codes.

5. Use PHP regular expression to match ID number

In PHP, you can use the preg_match function to match ID number. The following is an example:

$id_number = '110101199001010013'; // 待匹配的身份证号码
$pattern = '/^110000(19|20)d{2}(0[1-9]|1[012])(0[1-9]|[12][0-9]|3[01])d{3}[0-9Xx]$/'; // 匹配规则
if (preg_match($pattern, $id_number)) {
    echo '身份证号码格式正确';
} else {
    echo '身份证号码格式错误';
}

In this code, $id_number is the ID number that needs to be matched, and $pattern is the matching rule. If the ID number meets the matching rules, the output format is correct; otherwise, the output format is incorrect.

6. Summary

Using PHP regular expressions can easily match ID numbers. It is necessary to write corresponding regular expressions according to the administrative division codes of different provinces to match the address code, and then match the complete ID card number by combining the address code and the date of birth code. In practical applications, the ID number matching code can be encapsulated into a function for easy reuse.

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