Use regular expressions in golang to verify whether the input is a legal QQ number

Golang is a modern and efficient programming language with many powerful tools and libraries, including libraries for processing regular expressions. Regular expressions are a tool for matching strings and can be used to check whether a string matches a specific pattern. In this article, we will explore how to use regular expressions in Golang to verify QQ numbers.

QQ number is an online instant messaging tool launched by Tencent. It consists of a string of numbers, usually 5 to 11 digits, starting with 0. Verifying the legitimacy of a QQ number is often a common task, whether when developing online games or social applications.

First, we need to use the regexp package in Golang to process regular expressions. This package provides a Regexp type structure that can be used to write regular expressions and match them.

The following is a regular expression for verifying QQ numbers:

^[1-9][0-9]{4,10}$

Among them, ^ represents the beginning of the string, and $ represents the end of the string. [1-9] means that the first digit is a number between 1 and 9, [0-9]{4,10} means that the following 4 to 10 digits can be any number. Therefore, this regular expression can be used to verify QQ numbers with 5 to 11 digits starting with 0.

Next, we will use Golang to verify the legitimacy of the QQ number. The following is a function that uses a regular expression to check whether the input is a legal QQ number:

import "regexp"

func isValidQQ(qq string) bool {
    regexp := regexp.MustCompile(`^[1-9][0-9]{4,10}$`)
    return regexp.MatchString(qq)
}

This function accepts a string parameter qq, and then uses the regexp package to create a new regular expression variable. Then, it calls the Regexp.MatchString method to check whether the input parameter matches the pattern of the QQ number. Returns true if the match is successful, false otherwise.

Now, we can use our isValidQQ function to verify whether a QQ number is legal. The following is a simple program example:

func main() {
    qq1 := "0123456"
    if isValidQQ(qq1) {
        fmt.Println(qq1, "is a valid QQ number.")
    } else {
        fmt.Println(qq1, "is not a valid QQ number.")
    }

    qq2 := "1234567"
    if isValidQQ(qq2) {
        fmt.Println(qq2, "is a valid QQ number.")
    } else {
        fmt.Println(qq2, "is not a valid QQ number.")
    }
}

In the above example, we first pass a QQ number to the isValidQQ function, and then match the number with the regular expression. If the number conforms to the format of a QQ number, the output number is a legal QQ number. Otherwise, the output number is not a legal QQ number.

In the results, we can see that the first QQ number is illegal, and the second QQ number is a legal QQ number.

In summary, Golang’s built-in regexp package makes validating regular expressions very easy. Using regular expressions to check the legitimacy of QQ numbers is a simple but necessary task as it prevents applications from accepting or displaying unauthorized QQ numbers.

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