Let's talk about the use of golang == symbol

Golang, or Go programming language, is a statically typed, concurrent, and compiled programming language developed by Google. It is widely used in back-end service development, network application development, and cloud computing. Golang is a relatively young programming language, first launched in 2009, but it has become a popular choice among enterprise developers and the open source community.

Golang’s success is due to its simplicity, ease of learning, and efficient concurrency support. However, like other programming languages, it has some confusing features. Among them, the most commonly mentioned is the == operator. In this article, we will explore the differences between Golang and ==.

== Purpose

In Golang, the == operator is used to compare whether two values ​​are equal. It can be used to compare various types of data, including basic data types (such as integers, floating point types, strings), composite data types (such as arrays, slices, structures), and reference types (such as maps and pointers).

When we use == for comparison, it returns true if two values ​​are equal, otherwise it returns false.

Here is an example of how to use the == operator to compare two integers for equality:

package main

import "fmt"

func main() {
    a := 1
    b := 2

    if a == b {
        fmt.Println("a 等于 b")
    } else {
        fmt.Println("a 不等于 b")
    }
}

In the above code, a and b are two integer variables. In the if statement, we use the == operator to determine if they are equal. Since a and b are not equal, we will output that a is not equal to b.

== Problems

Although the == operator can be used to compare values ​​of different types, it can also easily lead to some problems. This is because in Golang, the == operator not only compares values ​​but also types. So if we compare two values ​​and they are of different types, then they will not be equal.

Here is an example that illustrates this problem:

package main

import "fmt"

func main() {
    var a int = 1
    var b uint = 1

    if a == b {
        fmt.Println("a 等于 b")
    } else {
        fmt.Println("a 不等于 b")
    }
}

In the above code, we compare a variable a of type int and a variable b of type uint. Since they are of different types, they are not equal. Therefore, we will output that a is not equal to b.

== and pointers

In Golang, you also need to pay attention to the comparison between the == operator and pointers. When you use the == operator to compare two pointers, it compares whether the values ​​they point to are equal. That is, it does not compare whether the memory addresses they point to are the same.

Here is an example of how to use the == operator to compare what two pointers point to:

package main

import "fmt"

func main() {
    var a *int = new(int)
    var b *int = new(int)

    *a = 1
    *b = 1

    if a == b {
        fmt.Println("a 和 b 指向的值相等")
    } else {
        fmt.Println("a 和 b 指向的值不相等")
    }
}

In the above code, we create two pointers to the int type pointer variables a and b. Then we set whatever they point to to 1. In the if statement, we use the == operator to compare whether what they point to is the same. Since their contents are the same, we output that the values ​​pointed to by a and b are equal.

It should be noted that although this comparison method is useful for what the pointer points to, when comparing two pointers, it usually does not need to compare whether the memory address pointed to by the pointer is the same. This is because in Golang, two pointers are equal if they point to the same memory address.

Conclusion

Through the discussion in this article, we can find that in Golang, when the == operator compares values, it not only compares the values ​​themselves, but also compares their types. So if we were to compare two values ​​of different types, they would not be equal. In addition, the == operator can also be used to compare whether the contents pointed to by the pointers are the same, but usually there is no need to compare whether the memory addresses pointed to by the pointers are the same.

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