How to verify if password contains spaces using regular expression in golang

In golang, regular expressions are a very powerful tool that can be used to detect whether a string matches a certain pattern. When verifying passwords, a common requirement is that the password cannot contain spaces. So, how to use regular expressions in golang to detect whether the password contains spaces? This article will introduce it to you in detail.

1. Overview of regular expressions

Regular expression is a language used to match strings. It can help developers quickly extract the required information from large amounts of text. . In golang, the regular expression matching function can be implemented by using the "regexp" package in the standard library. This package provides functions and types for building and matching regular expressions.

In golang, the syntax of regular expressions is roughly the same as that of other languages. Common metacharacters include the following:

• (): used for grouping, the operator can be modified priority.
• []: used to describe a character set.
• {}: Used to describe the number of repetitions. For example, {1,3} means matching characters repeated 1 to 3 times.
• *: Matches the previous character 0 or more times.
• : Matches the previous character 1 or more times.
• ?: Match the previous character 0 or 1 times.
• .: Can match any character (except newline).
• d: Matches any numeric character, equivalent to [0-9].
• D: Matches any non-numeric character, equivalent to ¹.
• w: Matches any alphabetic or numeric character, equivalent to [a-zA-Z0-9_].
• W: Matches any non-letter or numeric character, equivalent to ².
• s: Matches any space character (including space, tab, carriage return, etc.), equivalent to [
  ].
• S: Matches any non-space character.

2. Verify whether the password contains spaces

Now, we try to use regular expressions to verify whether the password contains spaces. Assuming that we have obtained the password entered by the user, we can use the following method to verify it:

package main

import (
    "fmt"
    "regexp"
)

func checkPassword(password string) bool {
    pattern := `^[^s]+$` // 定义正则表达式
    matched, err := regexp.MatchString(pattern, password) // 匹配字符串
    if err != nil {
        // 这里处理匹配错误的情况
    }
    return matched
}

func main() {
    password := "abc123" // 测试用例1，不包含空格，应返回true
    fmt.Println(checkPassword(password)) // 输出true

    password = "abc 123" // 测试用例2，包含空格，应返回false
    fmt.Println(checkPassword(password)) // 输出false
}

In the above example, we defined a function named "checkPassword", which accepts a string type The parameter "password" is used to verify whether the password meets the requirements. A variable named "pattern" is defined in the function to store the regular expression we want to match, that is, "^³ $". What this regular expression means is: the string must start with a non-whitespace character, end with a non-whitespace character, and the string cannot contain any whitespace characters.

In the function, we first use the "regexp.MatchString" function to match the string "password" to be detected and the regular expression "pattern". Returns true if the match is successful, false otherwise. It should be noted that if an error occurs during the matching process, a non-nil error object will be returned. Therefore, we need error handling in the code.

In the main function, we wrote two test cases, one containing spaces and one not containing spaces. After running the program, you can see that the output is as expected.

3. Summary

This article introduces how to use regular expressions in golang to verify whether the password contains spaces. By using regular expressions, we can easily detect whether a string matches a specific pattern. In golang, the standard library provides a package called "regexp" to help developers build and match regular expressions. Using this package, we can quickly implement string matching functions to achieve various verification needs.

---

1. 0-9 ↩
2. a-zA-Z0-9_ ↩
3. s ↩

The above is the detailed content of How to verify if password contains spaces using regular expression in golang. For more information, please follow other related articles on the PHP Chinese website!