golang slice map delete

In Golang, slice and map are both very commonly used data structures. Their deletion operations are also very important, because in practical applications we often need to delete certain elements or key-value pairs from existing slices or maps. This article will focus on how to delete slices and maps in Golang.

1. Deletion of slice in Golang

In Golang, there are usually two ways to delete elements in a slice: using the append function or using the copy function. These two methods are introduced below.

1.1 Use the append function to delete elements in a slice

It is more intuitive to use the append function to delete elements in a slice. The specific method is to re-splice the elements before and after the element to be deleted into a new one. slice. Here is a sample code:

// 删除slice中的某个元素 func removeSliceElement(slice []int, index int) []int { return append(slice[:index], slice[index+1:]...) }

In this example, we define a function called removeSliceElement, which accepts a slice of type []int and an index value of the element to be removed. The return value of the function is the new slice after deletion.

The specific steps are to first split the slice and take out the elements before and after the element to be deleted. Then re-splice these two elements into a new slice, and finally return the new slice.

1.2 Use the copy function to delete elements in the slice

It is also relatively simple to use the copy function to delete elements in the slice. The specific method is to move the elements after the element to be deleted forward to cover the element to be deleted. The following is a sample code:

// 删除slice中的某个元素 func removeSliceElement(slice []int, index int) []int { copy(slice[index:], slice[index+1:]) return slice[:len(slice)-1] }

In this example, a function named removeSliceElement is also defined, which accepts a slice of type []int and an index value of the element to be removed. The return value of the function is the new slice after deletion.

The specific steps are to move the elements after the element to be deleted forward through the copy function, overwriting the element to be deleted. Finally, subtract 1 from the length of the new slice to remove the overwritten elements, and return the new slice.

2. Deletion of map in Golang

In Golang, there are also two ways to delete the key-value pairs in the map: using the delete function or using a loop to delete. These two methods are introduced below.

2.1 Use the delete function to delete key-value pairs in the map

It is relatively simple to use the delete function to delete the key-value pairs in the map. The specific method is to delete the corresponding key-value pair through key. Here is a sample code:

// 删除map中的某个键值对 func removeMapValue(m map[string]int, key string) { delete(m, key) }

In this example, we define a function called removeMapValue, which accepts a map of type map[string]int and a key of the key-value pair to be deleted . The function has no return value, and the deletion operation is performed directly on the original map.

The specific steps are to pass in the key of the key-value pair to be deleted through the delete function, and then perform the delete operation.

2.2 Use loop deletion to delete key-value pairs in the map

Using loop deletion to delete key-value pairs in the map is more cumbersome, but in some cases it is more flexible than the delete function. The specific method is to loop through the map, filter out the key-value pairs to be deleted, and then delete them. The following is a sample code:

// 删除map中的某个键值对 func removeMapValue(m map[string]int, key string) { for k, v := range m { if k == key { delete(m, k) break } } }

In this example, a function named removeMapValue is also defined, which accepts a map of type map[string]int and the key of a key-value pair to be deleted. . The function has no return value, and the deletion operation is performed directly on the original map.

The specific steps are to loop through the map, filter out the key-value pairs to be deleted, and then perform the deletion operation. In this example, we only need to find the position of the key of the key-value pair to be deleted in the map, and then delete it through the delete function.

Summary

The above are the two ways to delete slices and maps in Golang. Using the append function, copy function, delete function or loop deletion are all common methods. Through these methods, we can easily delete slices and maps, making the program more flexible and efficient.

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