Golang formal parameter requirements exploration: parameter transfer efficiency, parameter initialization method

Exploration of Golang formal parameter requirements: parameter transfer efficiency, parameter initialization method

Go language is a statically typed programming language with efficient concurrency support and concise grammar. In the Go language, the method of passing formal parameters of functions has an important impact on the efficiency and performance of the program. This article will start from the perspective of Golang formal parameter requirements, explore the efficiency of parameter transfer and the method of parameter initialization, and provide specific code examples to illustrate.

1. Parameter passing efficiency

In the Go language, the parameter passing methods of functions are mainly divided into two types: value passing and reference passing. For value type parameters, a copy of the parameter is passed to the function when the function is called; while for reference type parameters, the address of the parameter is passed directly. The efficiency issues of value passing and reference passing are discussed below:

1. Value passing

The value passing method is more efficient when the parameters are smaller, because it only requires Make a memory copy. However, for larger data structures or objects, value transfer may cause performance degradation, because a copy of the entire data structure needs to be copied, which consumes a large amount of memory and time.

package main

import "fmt"

func modifyValue(num int) {
    num = num + 10
}

func main() {
    x := 10
    modifyValue(x)
    fmt.Println(x) // 输出结果仍为10
}

In the above example, although the value of the parameter num is modified in the modifyValue function, # is printed in the main function The value of ##x is still 10, indicating that value transfer will not change the original parameter value.

Passing by reference

The method of passing by reference is more efficient when the parameters are large, because only the address of the parameter needs to be passed, and no additional memory copies will be generated. . However, it should be noted that passing by reference may modify the value of the original parameter, so it needs to be used with caution.

package main

import "fmt"

func modifySlice(slice []int) {
    slice[0] = 100
}

func main() {
    nums := []int{1, 2, 3}
    modifySlice(nums)
    fmt.Println(nums) // 输出结果为[100 2 3]
}

In the above example, the

modifySlice function modifies the value of the parameter slice, affecting the value of the original parameter nums, so# The value of nums printed in the ##main function is [100 2 3]. 2. Parameter initialization method

In the Go language, there are many ways to initialize parameters, including using literal values, using the new function and using the make function. The three initialization methods are introduced below:

Using literal values

1. Using literal values ​​to initialize parameters is the simplest way, and initialization can be completed directly by assigning values.

package main

import "fmt"

func main() {
    num := 10
    str := "Hello"
    arr := []int{1, 2, 3}
    
    fmt.Println(num)
    fmt.Println(str)
    fmt.Println(arr)
}

In the above example, the integer variable

num

, the string variable str, and the integer slice arr are initialized through literal values. .

Use the new function

2. The new function is used to allocate memory space and return a pointer to the memory space.

package main

import "fmt"

func main() {
    numPtr := new(int)
    
    fmt.Println(*numPtr) // 输出结果为0
}

In the above example, an integer pointer

numPtr

is initialized using the new function, and the initial value is 0.

Using the make function

3. The make function is used to create reference type data structures such as slices, maps, and channels.

package main

import "fmt"

func main() {
    slice := make([]int, 3)
    m := make(map[string]int)
    
    fmt.Println(slice) // 输出结果为[0 0 0]
    fmt.Println(m) // 输出结果为map[]
}

In the above example, the make function is used to initialize an integer slice containing three elements

slice

and an empty string-to-integer mappingm . To sum up, this article discusses the efficiency of parameter transfer and the method of parameter initialization from the perspective of Golang formal parameter requirements, and provides specific code examples for illustration. In actual programming, it is necessary to choose the appropriate parameter transfer method and initialization method according to the specific situation to improve the efficiency and performance of the program.

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