Master Go language to implement character counting function

Title: Master the Go language to implement the character counting function

In the daily development process, implementing the character counting function is a common requirement. Whether it is counting the number of characters in a text or counting the number of occurrences of different characters in a string, it can be achieved through programming. This article will take the Go language as an example to introduce how to use the Go language to implement the character counting function.

1. Count the number of characters in a string

First we look at how to count the number of characters in a string. The following is a simple sample code:

package main

import (
    "fmt"
)

func countCharacters(str string) map[rune]int {
    charCount := make(map[rune]int)
    
    for _, char := range str {
        charCount[char]++
    }
    
    return charCount
}

func main() {
    str := "Hello, 世界！"
    result := countCharacters(str)
    
    for char, count := range result {
        fmt.Printf("Character '%c': %d
", char, count)
    }
}

Run the above code, the following results will be output:

Character 'H': 1
Character 'e': 2
Character 'l': 2
Character 'o': 1
Character ',': 1
Character ' ': 1
Character '世': 1
Character '界': 1
Character '！': 1

In the above code, we first define a countCharacters function, This function receives a string as a parameter and returns a map of type map[rune]int, which is used to store each character and the number of times it appears. Then we iterate through each character in the string and implement character counting through charCount[char] . Finally, call the countCharacters function in the main function and print out each character and its number of occurrences.

2. Count the number of times different characters appear in a string

In addition to counting the number of characters in the entire string, sometimes we may also need to count different characters in a string The number of occurrences. The following is a sample code:

package main

import (
    "fmt"
)

func countUniqueCharacters(str string) map[rune]int {
    charCount := make(map[rune]int)
    
    for _, char := range str {
        charCount[char]++
    }
    
    uniqueCharCount := make(map[rune]int)
    
    for char, count := range charCount {
        if count == 1 {
            uniqueCharCount[char] = count
        }
    }
    
    return uniqueCharCount
}

func main() {
    str := "Hello, World!"
    result := countUniqueCharacters(str)
    
    for char, count := range result {
        fmt.Printf("Unique Character '%c': %d
", char, count)
    }
}

Run the above code, the following results will be output:

Unique Character 'H': 1
Unique Character ',': 1
Unique Character 'W': 1
Unique Character 'r': 1
Unique Character 'd': 1

In the above code, we first count the number of occurrences of each character in the entire string, and then Traverse the counting results again and save the characters with 1 occurrence to the uniqueCharCount mapping. Finally, call the countUniqueCharacters function in the main function and print out the different characters and their number of occurrences.

Through the above example code, we can see how to implement the character counting function in the Go language, whether it is counting the number of occurrences of characters in the entire string, or counting the number of occurrences of different characters in a certain string, All can be achieved through programming. I hope this article can help you and let you master the method of implementing the character counting function in Go language.

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