Let’s talk about how to use golang slicing method

Slices in Go language (golang) are dynamic arrays that can grow and shrink automatically. A slice is a structure that encapsulates a pointer to the underlying array, the number of elements, and the capacity.

Since the implementation of slicing is based on the underlying array, the operation of slicing is largely subject to the underlying array. In this article, we will discuss some common slicing methods and their usage.

1. Create a slice

First, we need to create a slice. There are two ways to create slices: using the make function and direct declaration.

Use the make function:

a := make([]int, 5) //Create an integer slice of length 5

The make function accepts two parameters : The first parameter is the type of the slice element, and the second parameter is the length of the slice. If you want to specify the capacity, you can pass the third parameter:

b := make([]string, 5, 10) //Create a string slice with a length of 5 and a capacity of 10

Direct declaration:

c := []int{1, 2, 3, 4, 5} //Create an integer slice containing 5 elements

Note, use this The length and capacity of the slices created in this way are equal.

2. Access to slices

Accessing slice elements by index is the same as for arrays. For example, to access the first element, you would do this:

fmt.Println(c[0])

3. Modification of slices

Since the slice is variable, we can modify the element value through the index:

c[0] = 10 //Change the first element to 10

4. slice Append

Use the append method of the slice to add elements to the slice. If the slice capacity is not large enough to accommodate all elements, it will automatically expand.

For example, we can add elements to the end of the slice using the following method:

c = append(c, 6, 7, 8) //Add 3 elements at the end of the slice

When adding a single element, we can write like this:

c = append(c, 9) //Add an element at the end of the slice

5. Copy of the slice

Slices can be copied using the copy function. The first parameter of the copy function is the target slice, and the second parameter is the source slice.

For example:

d := make([]int, len(c))
copy(d, c)

6. Interception of slice

Use the [start:end] form of the slice to intercept the slice and get a new slice. start represents the starting position (closed interval) to be intercepted, and end represents the end position (open interval).

For example:

e := c[2:5] //Intercept the slice containing the third to fifth elements

If start is omitted, the default is 0 ;If end is omitted, it defaults to the length of the slice.

7. Deletion of slices

There is no direct way to delete slice elements in Go. However, we can delete elements indirectly by rebuilding a new slice.

For example, we can delete the third element using the following code:

f := append(c[:2], c[3:]...)

In this way, f is a new slice in which the third element has been deleted.

Summary

Slicing is a very powerful data type, which can help us operate data more conveniently. In this article, we introduce some common slice operation methods, including creation, access, modification, append, copy, interception and deletion. If you want to master slicing in the Go language, you can deepen your understanding by reading the official documentation.

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