String in Go

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String representation

Double quoted string

The escaped characters in the string will be escaped and output after escaping

// Double quoted string
	/* Hello world! * /
str := "Hello \n world!"
fmt.Println(str)
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Backquoted string

Escaped characters in a string are not escaped and output as is

// Backquotes string
	/* Hello \n World! * /
str = `Hello \n World! `
fmt.Println(str)
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Empty strings are represented by “”, which is the zero value of the string

Length of string

We can use the len() function to get the length of the string bytes

Note that this function takes the sum of all character lengths in the string, not the number of characters

	/* Pure letters, to get the length of the output: 15 */
	str = `Hello \n World! `
	fmt.Println(len(str))

	/* Chinese letters, to get the length of the output: 8 */
	str = "You Go"
	fmt.Println(len(str))
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Call utf8.runecountinString () to get the number of characters in the string, not the number of bytes

/* A Chinese letter in bytes. The output is 8 */
str = "You Go"
fmt.Println(len(str))

/* The character length is 4 */
fmt.Println(utf8.RuneCountInString(str))
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Traversal string

// Go for... Range decodes implicit types when working with strings
// Iterate over the string with Chinese characters
str = "You Go"
for i, v := range str {
   fmt.Printf("Index: %d, value: %c \n", i, v)
}

// Iterate over a string of pure letters
str = `Hello World! `
for i, v := range str {
   fmt.Printf("Index: %d, value: %c \n", i, v)
}
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Concatenation of strings

Overloaded operators +, +=

	// Direct concatenation of strings
	str = "Hello " + "world!"
	str += " I am a gopher"
	fmt.Println(str)
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strings.Join()

// When concatenating multiple strings, add a string to separate them
str = strings.Join([] string{"Hello"."world"}, " and ")
fmt.Println(str)
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bytes.Buffer

// bytes.buffer concatenates a string
var buffer bytes.Buffer
buffer.WriteString("Hello")
buffer.WriteString(" world!")
fmt.Println(buffer.String())
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strings.Builder

// strings.Builder concatenates strings
var builder strings.Builder
builder.WriteString("I")
builder.WriteString(" am")
builder.WriteString(" a")
builder.WriteString(" gopher!")
fmt.Println(builder.String())
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The first two methods of concatenating strings have some memory and performance waste. It is recommended to use the latter two methods for concatenating strings

Common string operations

Determine the prefix

/ / prefix
res := strings.HasPrefix("isOpen"."is")
fmt.Println(res)
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Determine the suffix

/ / the suffix
res = strings.HasSuffix("finished"."ed")
fmt.Println(res)
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Split string

res2 := strings.Split("Hi! Shaosiming! You are nice!"."!")
for _, v := range res2 {
   fmt.Println(v)
}
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Returns the substring index

	// The position first appeared from the left
	index := strings.Index("Hi shaosiming"."i")
	fmt.Println(index)

	// First appearing position from the right
	index = strings.LastIndex("Hi shaosiming"."i")
	fmt.Println(index)
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String substitution

The first argument is the string to operate on

The second argument is the string to be replaced

The third argument is the string to be replaced with

The fourth parameter is the number of substitutions. -1 represents all substitutions

str = strings.Replace("Hi! Shaosiming! You are nice!"."!".",".- 1)
fmt.Println(str)
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String to uppercase String to lowercase

/ / caps
fmt.Println(strings.ToUpper("Hi Shaosiming"))

/ / lowercase
fmt.Println(strings.ToLower("Hi Shaosiming"))
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The number of occurrences of characters in a string

fmt.Println(strings.Count("hi shaosiming"."i"))
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The inclusion relationship of a string

fmt.Println(strings.Contains("hi shaosiming"."ming"))
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