golang切片append(golang切片赋值)-捕鱼10元起上10元下

introduction

golang, also known as go, is a programming language developed by google in 2007. it has gained popularity over the years due to its simplicity, fast compile time, and efficient memory management. one of the built-in data types in golang is a slice, which is a dynamic-sized array that allows appending elements. in this article, we will explore the golang slice append function and its usage.

golang slice append function

the built-in append function in golang is used to add elements to a slice. the syntax of the append function is as follows:

func append(slice []type, elems ...type) []type

the first argument of the function is the slice to which elements are added, and the remaining arguments are the elements to be added. the function returns a new slice containing all the elements of the original slice and the added elements. if the capacity of the original slice is sufficient to hold all the elements, the function reuses the underlying array. otherwise, it creates a new underlying array and copies the elements from the old array to the new one.

usage

let's look at an example of using the append function to add elements to a slice:

// create a slice
slice := []int{1, 2, 3}
// add elements to the slice
slice = append(slice, 4, 5, 6)
// print the slice
fmt.println(slice) // output: [1 2 3 4 5 6]

we can see that the append function adds elements 4, 5, and 6 to the original slice [1, 2, 3], resulting in a new slice [1, 2, 3, 4, 5, 6].

the append function can also be used to concatenate two slices, as follows:

// create two slices
slice1 := []int{1, 2, 3}
slice2 := []int{4, 5, 6}
// concatenate the two slices
slice3 := append(slice1, slice2...)
// print the concatenated slice
fmt.println(slice3) // output: [1 2 3 4 5 6]

in this example, the slice2 is appended to the end of slice1, resulting in a new slice [1, 2, 3, 4, 5, 6]. note that we use the ellipsis (...) to pass a slice as a variadic argument.

conclusion

in conclusion, the append function in golang is a useful built-in function for adding elements to a slice. it allows dynamic resizing of a slice and efficient memory management. when appending elements to a slice, it is important to keep in mind that the function may create a new underlying array and copy the elements, which can be costly in terms of memory allocation and performance. therefore, it is recommended to preallocate the capacity of a slice if possible to avoid unnecessary memory allocation.