Processing of slicing and mapping in Golang function parameter passing

When passing function parameters in Go, slices and maps pass references instead of values. Modification of the slice in the function will affect the slice in the calling function. Mapping modifications in a function will also affect the mapping in the calling function. If you need to pass a copy, you can use the copy function. When multiple goroutines access slices or maps at the same time, data competition should be considered and mutexes should be used to synchronize access.

Slicing and mapping in function parameter passing in Go

In Go, function parameters can be value types or reference types . Value types are copied when parameters are passed, while reference types are passed by reference.

Slice

Slice is a reference type, so its reference will be passed when the function parameter is passed. This means that any changes made to the slice elements in the function will be reflected in the function that calls it.

Example:

func modifySlice(slice []int) {
    slice[0] = 100 // 修改切片元素
}

func main() {
    slice := []int{1, 2, 3}
    modifySlice(slice) // 传递切片引用
    fmt.Println(slice) // 输出：[100 2 3]
}

Mapping

Mapping is also a reference type, and its reference is also passed when function parameters are passed. Similar to slicing, any changes made to the map in a function will be reflected in the function that calls it.

Example:

func modifyMap(m map[string]int) {
    m["key"] = 100 // 修改映射元素
}

func main() {
    m := make(map[string]int)
    m["key"] = 1
    modifyMap(m) // 传递映射引用
    fmt.Println(m["key"]) // 输出：100
}

Notes

• Passing a copy of the slice or map: Sometimes it is more appropriate to pass a copy of a slice or map rather than a reference. A copy can be created using the copy function.
• Prevent data race: When multiple goroutines access the same slice or map at the same time, data race may occur. To prevent this, you can use a mutex lock (sync.Mutex) to synchronize access to the slice or map.

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