what is golang byte

Each element in the string is called a "character", and characters can be obtained when traversing or individually obtaining string elements.

There are two types of characters in Go language:

One is uint8 type, or byte type, Represents a character in ASCII code. (Recommended learning: go)

The other is the rune type, which represents a UTF-8 character. When you need to process Chinese, Japanese or other compound characters, you need to use the rune type. . The rune type is equivalent to the int32 type. The

byte type is an alias for uint8, which is completely fine for traditional ASCII-encoded characters that only occupy 1 byte, such as var ch byte = 'A', and the characters are enclosed in single quotes.

In the ASCII code table, the value of A is 65, and in hexadecimal notation it is 41, so the following writing is equivalent:

var ch byte = 65 或 var ch byte = '\x41'      //（\x 总是紧跟着长度为 2 的 16 进制数）

In addition One possible way to write it is \ followed by an octal number of length 3, for example \377.

Go language also supports Unicode (UTF-8), so characters are also called Unicode code points or runes, and are represented by int in memory. In documents, the format U hhhh is generally used, where h represents a hexadecimal number.

When writing Unicode characters, you need to add the prefix \u or \U before the hexadecimal number. Because Unicode occupies at least 2 bytes, we use int16 or int type to represent it. If you need to use 4 bytes, use the \u prefix, if you need to use 8 bytes, use the \U prefix.

var ch int = '\u0041'
var ch2 int = '\u03B2'
var ch3 int = '\U00101234'
fmt.Printf("%d - %d - %d\n", ch, ch2, ch3) // integer
fmt.Printf("%c - %c - %c\n", ch, ch2, ch3) // character
fmt.Printf("%X - %X - %X\n", ch, ch2, ch3) // UTF-8 bytes
fmt.Printf("%U - %U - %U", ch, ch2, ch3)   // UTF-8 code point

Output:

65 - 946 - 1053236
A - β - r
41 - 3B2 - 101234
U+0041 - U+03B2 - U+101234

The format specifier %c is used to represent characters. When used with characters, %v or %d will be output An integer used to represent the character. %U outputs a string in the format of U hhhh.

The Unicode package has some built-in functions for testing characters. The return value of these functions is a Boolean value, as shown below (where ch represents the character):

判断是否为字母：unicode.IsLetter(ch)
判断是否为数字：unicode.IsDigit(ch)
判断是否为空白符号：unicode.IsSpace(ch)

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