Detailed explanation of golang character slicing usage

Golang, as a fast, efficient and safe programming language, provides many useful methods for string processing, among which the use of character slicing is very important. Character slicing means that a string is divided into multiple character parts, and each character can be accessed independently, which is very practical in string processing. This article will introduce the application of character slicing in golang.

1. Definition of character slice

In Golang, character slice is defined as follows:

var slice []Type

Among them, Type can be any type supported by Golang, for example int, float64, string, bool, etc. In character slicing, string type character slicing is usually used, which is defined as follows:

var strSlice []string

2. Creation of character slices

There are two ways to create character slices: Use the make function and direct assignment method:

//使用 make 函数创建
var strSlice []string = make([]string, 3)

//直接赋值方式创建
var strSlice2 []string = []string{"hello", "world"}

Among them, using the make function to create a character slice requires passing in two parameters. The first parameter is the length of the slice, and the second parameter is the capacity of the slice. The capacity definition The size of the underlying array of the slice. If no capacity is specified, the length and capacity default to zero.

3. Add and delete character slices

Elements in character slices can be added or deleted dynamically. Use the append function to add elements and use slice syntax (slice[:index] slice [index 1:]) deletes the element.

//在字符切片的末尾添加一个元素
strSlice = append(strSlice, "hello")

//在字符切片的指定位置插入一个元素
strSlice = append(strSlice[:1], append([]string{"world"}, strSlice[1:]...)...)

//删除字符切片的指定元素
strSlice = append(strSlice[:2], strSlice[3:]...)

Among them, the append function allows one or more elements to be added to the end of the character slice. The syntax is as follows:

slice = append(slice, elem1, elem2, elem3)

If the number of added elements is too many, you can use the slice syntax to add ：

slice = append(slice, []T{elem1, elem2, elem3}...)

When deleting elements in a character slice, we need to use slicing syntax to take out the subscript corresponding to the element to be deleted, and generate a new slice through a connection operation to delete the specified element.

4. Splicing and copying of character slices

Character slices can be spliced ​​into multiple slices through connection operations. It also supports copy operations. Use the copy function to merge one slice into Copy the elements to another slice:

//字符切片的拼接
slice1 := []string{"hello", "world"}
slice2 := []string{"golang", "is", "awesome"}

slice3 := append(slice1, slice2...)

//字符切片的复制
slice4 := make([]string, len(slice1))
copy(slice4, slice1)

Among them, the splicing operation uses the append function to directly add one slice to the end of another slice. At the same time, pay attention to the syntax append(slice1, slice2...) Three dots represent an indefinite number of slice elements.

The copy operation uses the copy function, which requires passing two parameters, the target slice and the source slice.

5. Character slice traversal

Character slices can be traversed using for loops. Here we introduce two commonly used traversal methods: for loops and range keywords.

//for 循环遍历
for i := 0; i < len(strSlice); i++ {
    fmt.Println(strSlice[i])
}

//range 关键字遍历
for index, value := range strSlice {
    fmt.Println(index, value)
}

The above two traversal methods can meet most needs. When traversing using the range keyword, the index and value obtained can be specific to the index and value of each element.

6. Application of character slicing

Character slicing is very common in Golang. Its application scenarios include string concatenation operations, processing command line parameters, splitting strings, etc. . Below we introduce some of the common application scenarios.

6.1 String concatenation operation

String concatenation operation is one of the most commonly used application scenarios of character slicing. For example, to concatenate multiple strings into one string, you can use the strings.Join function ：

strSlice := []string{"hello", "world"}

str := strings.Join(strSlice, ", ")
fmt.Println(str) // output: "hello, world"

6.2 Processing command line parameters

Golang provides a method to access command line parameters through the os package. Use os.Args to obtain a character slice containing all command line parameters, as follows Shown:

for index, value := range os.Args {
    fmt.Printf("args[%d]=%s\n", index, value)
}

The above code will output all command line parameters when the current program is running.

6.3 Splitting strings

Golang provides the strings package to process strings. The strings.Split function can split a string into multiple substrings based on the specified delimiter. , and stored in character slices:

str := "hello,world,golang"
strSlice := strings.Split(str, ",")

for _, value := range strSlice {
    fmt.Println(value)
}

The above code will output three split strings: hello, world and golang.

7. Summary

This article introduces the definition, creation, addition and deletion, splicing and copying, traversal and application scenarios of character slicing in Golang. Character slicing solves the problem of character slicing very well. It solves many problems in string processing, and its ease of use and efficiency have been recognized by developers.

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