golang slice method Op

[Foreword]

Slice in Go language is a very common data structure and is often used for dynamic array operations. In use, we often need to perform operations such as adding, deleting, checking, and modifying slices, and the Go language provides some built-in methods to implement these operations. This article will introduce in detail the basic usage and common methods of slicing in the Go language.

[1. Definition of slice]

A slice is a variable-length sequence, defined as:

var arr []type

The type here can be any type, such as int , string, etc. You can also use the make() method to directly create a slice:

arr := make([]type, len, cap)

where len represents the length of the slice and cap represents the capacity of the slice. What needs to be noted here is that the capacity of the slice is greater than or equal to the length.

[2. Basic operations of slicing]

2.1 Traversal of slices

You can use the range keyword to traverse slices. The code example is as follows:

arr := []string{"hello", "world", "go"}

for index, value := range arr {
    fmt.Printf("index:%d, value:%s
", index, value)
}

Output The result is:

index:0, value:hello
index:1, value:world
index:2, value:go

2.2 Adding slices

To add elements to a slice, you can use the append() method, as shown below:

var arr []string
arr = append(arr, "hello")

It should be noted here that using After the append() method, its return value needs to be reassigned to the slice.

2.3 Deletion of slices

To delete elements in a slice, you can use the built-in delete() method, as shown below:

arr := []string{"hello", "world", "go"}

arr = append(arr[:1], arr[2:]...)

The syntax here is very tricky, we It can be divided into three parts:

• arr[:1]: represents elements from 0 to 1 (excluding 1), that is, "hello";
• arr[ 2:]: means from 2 to the last element of the array (excluding 2), that is, "go";
• ... means merging two slices.

The final result is to delete the element "world" with index 1.

2.4 Modification of slices

Modify the elements in the slice by directly assigning values ​​through subscripts, as shown below:

arr := []string{"hello", "world", "go"}

arr[1] = "Golang"

fmt.Println(arr)

The output result is:

[hello Golang go]

[3. Commonly used methods of slicing]

Here are some commonly used slicing methods:

3.1 len() method

The len() method is used to obtain slices The length of the slice, the code example is as follows:

arr := []string{"hello", "world", "go"}

fmt.Println(len(arr))

The output result is:

3

3.2 cap() method

The cap() method is used to obtain the capacity of the slice, the code example is as follows :

arr := make([]string, 3, 5)

fmt.Println(cap(arr))

The output result is:

5

3.3 copy() method

The copy() method can copy the value of one slice to another slice. The code example is as follows :

var arr1 = []string{"apple", "banana", "orange"}

var arr2 = make([]string, 3)

copy(arr2, arr1)

fmt.Println(arr2)

The output result is:

[apple banana orange]

3.4 append() method

append() method is used to add elements to the slice. The code example is as follows:

arr := []string{"hello", "world", "go"}

arr = append(arr, "Golang")

fmt.Println(arr)

The output result is:

[hello world go Golang]

3.5 append() method and expansion

When the capacity of the slice is not enough to accommodate new elements, the append() method will automatically expand the capacity, and the expansion conditions It is:

• If the length of the new element is less than 1024, the capacity of the slice is doubled;
• If the length of the new element is greater than or equal to 1024, each expansion increases the original capacity by 1 /4 until capacity is sufficient.

3.6 Variable parameters of the append() method

The input parameters of the append() method can be variable parameters, and multiple elements can be added to the slice. The code example is as follows:

arr := []string{"hello", "world", "go"}

arr = append(arr, "Golang", "Python")

fmt.Println(arr)

The output result is:

[hello world go Golang Python]

[Summary]

This article provides a detailed introduction to the basic usage and common methods of slicing in the Go language. I hope it will be useful to everyone. help. In actual code, the flexible use of slicing can make our code more concise and efficient.

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