Golang implements wildcards

Wildcard is a search pattern commonly used in many programming languages, which can help programmers find matching files or information faster. In golang, the implementation of wildcards is also very simple. This article will introduce you how to use wildcards in golang.

1. What is a wildcard?

A wildcard character refers to a special character that can be used to represent any character, or a group of characters, in a file name or search string. In Unix file systems, wildcards are often used for file name pattern matching, for example *.txt will match all files ending with .txt.

2. Use wildcards

In golang, a function called filepath.Match is used to support the implementation of wildcards. The basic form of this function is:

func Match(pattern, name string) (matched bool, err error)

Among them, the pattern parameter specifies a wildcard pattern, and the name parameter is required The matching string. If the match is successful, the function returns true; otherwise, it returns false. If no wildcard is specified for the pattern parameter, the function will directly compare the pattern and name strings for equality.

The wildcard characters supported by the filepath.Match function include the following:

1. *: represents any character, including the empty string.
2. ?: Represents a single arbitrary character.
3. [...]: Represents a set of characters, the characters of which can be represented by - to represent a range. For example, [a-z] means all lowercase letters. If the first character inside the square brackets is !, it means a character that is not in this group. For example, [!a-z] represents all characters that are not between a and z.
4. : Used to escape wildcard characters, such as * to match the * character itself.

Here is an example of using wildcards:

package main

import (

"fmt"
"path/filepath"

)

func main( ) {

fileNames := []string{"file1.txt", "file2.mp3", "image.jpg", "song.mp3"}
for _, fileName := range fileNames {
    matched, err := filepath.Match("*.mp3", fileName)
    if err != nil {
        fmt.Println("Error matching pattern:", err)
        return
    }
    if matched {
        fmt.Println("Matched:", fileName)
    }
}

}

In the above example, we define a slice containing four file names, and then use the filepath.Match function to find files ending with ".mp3". The execution results are as follows:

Matched: file2.mp3
Matched: song.mp3

As you can see, the output results include file names that match the wildcard pattern.

3. Summary

It is very simple to implement wildcards in golang. You only need to call the filepath.Match function and specify a wildcard pattern. By studying this article, you have learned the basic knowledge and usage of wildcards in golang. I hope it will be helpful to your programming work.

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