How to judge golang characters

Golang is a relatively new programming language. It has many features and advantages, such as high concurrency, good memory management, and simplicity and ease of learning. However, due to its special syntax and character set, it may be difficult for some beginners to judge characters and strings. Therefore, this article will introduce how to determine characters in Golang.

1. Golang character set

In Golang’s character set, each character consists of one or more bytes. The default length of a character is 1 byte, but some characters may consist of multiple bytes, depending on the character encoding used for the character.

The character sets and encoding methods in Golang are as follows:

1. ASCII code

ASCII code is the earliest character encoding method, it only Can represent English characters and some commonly used symbols. ASCII code uses 7 bits to represent a character, the highest bit is 0, and can represent 128 characters.

In Golang, the byte type is used to represent ASCII code, which can also be represented by explicit conversion of the integer type. For example:

var ch byte = 'A' // 直接使用字符字面量来表示 ASCII 码
var asciiCode int = int(ch) // 通过显式转换将 byte 类型转为 int 类型

2. Unicode code

Unicode code is a relatively new character encoding method that can represent all characters and symbols in the world, including characters from different countries and symbols. Unicode codes are represented in Golang using the rune type, or through explicit conversion of integer types. For example:

var ch1 rune = '世' // 直接使用 Unicode 字符字面量来表示
var ch2 rune = 'u4e16' // 也可以使用 Unicode 编码来表示，u4e16 表示 '世'
var unicodeCode int = int(ch1) // 将 rune 类型转换为 int 类型

It should be noted that since the length of Unicode code may exceed 1 byte, when processing Unicode strings, you need to pay attention to the length information of the characters.

3. UTF-8 encoding

UTF-8 encoding is one of the most commonly used Unicode encoding methods. It uses variable-length bytes to represent characters. The specific encoding method is as follows:

• For ASCII code characters, UTF-8 encoding is the same as ASCII code encoding, using 1 byte to represent;
• For non-ASCII characters, UTF-8 encoding uses multiple bytes to represent, where the high bit of the first byte identifies the total number of bytes required for encoding the character.

In Golang, you can use the string type string to represent UTF-8 strings. For example:

var s string = "Hello, 世界" // 使用字符串字面量表示 UTF-8 字符串
var byteSlice []byte = []byte(s) // 将字符串转为 byte 数组，每个字符使用 1 个字节表示
var runeSlice []rune = []rune(s) // 将字符串转为 rune 数组，每个字符可能使用多个字节表示

2. Character judgment methods in Golang

In Golang, you can use multiple methods to judge characters. Here are some commonly used methods.

1. Judge character length

Due to different character encoding methods, a character may be composed of multiple bytes. Therefore, when operating on a string, you need to first determine the length of the characters. You can use the len function and the []rune type to achieve:

func GetCharLength(s string) int {
    // 将字符串 s 转为 rune 类型的切片
    runeSlice := []rune(s)
    // 获取该切片的长度
    length := len(runeSlice)
    return length
}

2. Determine whether the character is an English letter

in In Golang, you can use the IsLetter function in the unicode package to determine whether a character is an English letter. For example:

func IsLetter(ch rune) bool {
    return unicode.IsLetter(ch)
}

3. Determine whether a character is a number

In Golang, you can use the IsDigit function in the unicode package To determine whether a character is a number. For example:

func IsDigit(ch rune) bool {
    return unicode.IsDigit(ch)
}

4. Determine whether the character is Chinese

In Golang, you can use Is(0x4e00, 0x9fff in the unicode package ) function to determine whether a character is Chinese. For example:

func IsChinese(ch rune) bool {
    return unicode.Is(unicode.Han, ch)
}

5. Determine whether the character is a space

In Golang, you can use the IsSpace function in the unicode package To determine whether a character is a space. For example:

func IsSpace(ch rune) bool {
    return unicode.IsSpace(ch)
}

3. Summary

This article introduces the basic knowledge and common judgment methods of character sets in Golang. For beginners, it is very important to master the representation and judgment of characters in Golang. I hope readers can better understand characters and strings in Golang through the introduction of this article.

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