How to use regular expressions to verify postal codes in golang

With the popularization of the Internet and the rise of e-commerce, zip code has increasingly become an indispensable parameter for online transactions. In golang programming, verifying the legitimacy of the zip code is a very common need. This article will introduce how to use regular expressions to verify the validity of the zip code.

1. Format of postal code

Let’s first understand the format requirements that postal codes should have. Currently, the internationally accepted postal code format is 5 digits. Some countries or regions have The zip code may contain other characters. For example, China's postal code format is 6 digits. Regardless of the format of the postal code, they should meet the following requirements:

1. The postal code only contains numbers or letters or specific characters
2. The length of the postal code does not exceed the specified length
3. The zip code should be legal
4. Use regular expressions to verify the zip code

Using golang's built-in regular expression library can easily verify the validity of the zip code. The following is a regular expression example code to verify China's 6-digit postal code:

func VerifyPostalCode(code string) bool {
    if matched, err := regexp.MatchString(`^d{6}$`, code); !matched || err != nil {
        return false
    }
    return true
}

Through the above code, we can verify whether a string is a 6-digit postal code. If the input does not meet the conditions, false will be returned. Otherwise return true.

d in the regular expression represents a numeric character, {6} is used to specify that the previous numeric character must appear 6 times. The ^ at the beginning of the string and the $ at the end represent the beginning and end of the string respectively.

For zip codes in other formats, we can write the corresponding regular expressions in a similar way. For example, the zip code format of the United States is ^d{5}([-]d{4})?$, where [-] represents a dash character, followed by d{4} represents a combination of four numeric characters. This format allows four digits to be added to the end of the zip code. Similarly, we can write postal code verification rules for other countries or regions to meet the needs of practical applications.

3. Verify zip code

Some application scenarios need to verify not the complete zip code, but the zip code. The postal code consists of the first part of the postal code. For example, the postal code of China is the first two digits of the postal code.

The following is a regular expression sample code to verify the Chinese postal code:

func VerifyPostalDistrict(code string) bool {
    if matched, err := regexp.MatchString(`^d{2}$`, code); !matched || err != nil {
        return false
    }
    return true
}

Similar to verifying the complete postal code, we can design different verification rules according to actual needs so that during the programming process Deal with every situation.

4. Summary

Using regular expressions to verify the validity of zip codes is a very common technique. In golang programming, this functionality is easily achieved using the built-in regular expression library. In practical applications, we need to combine specific needs and write corresponding regular expressions to meet various verification requirements.

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