Detailed introduction to how to use Golang built-in functions

Golang is a very powerful programming language that provides many built-in functions to facilitate developers' programming. In this article, we will introduce in detail how to use Golang's built-in functions for developers' reference.

1. make function

The make function is mainly used to create a data type object (slice, map or channel) and initialize its size. The basic syntax of the make function is as follows:

make(T, args)

Among them, T represents the data type to be created, args represents optional parameters, and the specific usage method varies according to the data type.

For example, create a slice of int type with a length of 10 and initialize it to 0:

s := make([]int, 10)

Create a map with a length of 10 and initialize it to empty:

m := make(map[int]string, 10)

2. new function

The new function is used to allocate a memory space and return its address. The basic syntax of the new function is as follows:

new(T)

Among them, T represents the data type to allocate space.

For example, allocate a memory space of type int:

p := new(int)

3. append function

The append function is used to add one or more at the end of the slice elements and returns the slice after adding the elements. The basic syntax of the append function is as follows:

append(slice []T, elements ...T) []T

Among them, slice represents the slice to which elements are to be added, and elements represents the elements to be added. Their data types are all T.

For example, add an element at the end of slice:

s := []int{1, 2, 3}
s = append(s, 4)

4. len function

The len function is used to obtain slice, map, string and other types length. The basic syntax of the len function is as follows:

len(v)

Among them, v represents the variable to obtain the length.

For example, get the length of a slice:

s := []int{1, 2, 3}
l := len(s)

5. copy function

The copy function is used to copy the elements in one slice to another slice , and returns the number of copied elements. The basic syntax of the copy function is as follows:

copy(dst []T, src []T) int

Among them, dst represents the slice to be copied to, src represents the slice to be copied, and the data types of both slices are T.

For example, copy one slice to another slice:

s1 := []int{1, 2, 3}
s2 := make([]int, 3)
copy(s2, s1)

6. panic function

The panic function is used to raise a runtime error, the program will Interrupt execution and print an error message. The basic syntax of the panic function is as follows:

panic(v interface{})

Among them, v represents the information to panic.

For example, trigger a panic error:

if err != nil {
    panic(err)
}

7. recover function

Therecover function is used to capture errors caused by panic and process them. The recover function can only be used in the defer function to repair the error state of the program and continue execution. The basic syntax of the recover function is as follows:

recover() interface{}

For example, use the recover function in the defer function:

defer func() {
    if err := recover(); err != nil {
        fmt.Println(err)
    }
}()

8. close function

close function is used to close A channel, that is, stop reading or writing operations on the channel. The basic syntax of the close function is as follows:

close(ch)

Among them, ch represents the channel to be closed.

For example, close a channel:

ch := make(chan int)
close(ch)

The above is an introduction to how to use Golang's built-in functions. We encourage developers to use these functions flexibly in programming to improve development efficiency and program quality.

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