How to delete an element from a Slice in Golang

by

Order matters

If you want to keep your array ordered, you have to shift all of the elements at the right of the deleting index by one to the left. Hopefully, this can be done easily in Golang:

func remove(slice []int, s int) []int {
    return append(slice[:s], slice[s+1:]...)
}

However, this is inefficient because you may end up with moving all of the elements, which is costly.

Order is not important

If you do not care about ordering, you have the much faster possibility to replace the element to delete with the one at the end of the slice and then return the n-1 first elements:

func remove(s []int, i int) []int {
    s[i] = s[len(s)-1]
    return s[:len(s)-1]
}

With the reslicing method, emptying an array of 1 000 000 elements take 224s, with this one it takes only 0.06ns.

This answer does not perform bounds-checking. It expects a valid index as input. This means that negative values or indices that are greater or equal to the initial len(s) will cause Go to panic.

Slices and arrays being 0-indexed, removing the n-th element of an array implies to provide input n-1. To remove the first element, call remove(s, 0), to remove the second, call remove(s, 1), and so on and so forth.

More Related Contents:

  1. slice member of a struct pointer is not updated [closed]
  2. Are slices passed by value?
  3. Concatenate two slices in Go
  4. Can I concurrently write different slice elements
  5. What is a concise way to create a 2D slice in Go?
  6. range over interface{} which stores a slice
  7. Can I construct a slice of a generic type with different type parameters?
  8. How do I reverse a slice in go?
  9. Why can’t I append to a slice that’s the property of a struct in golang?
  10. Big O of append in Golang
  11. How to inspect slice header?
  12. Slice chunking in Go
  13. Create a generic channel
  14. How to use a module that is outside of “GOPATH” in another module?
  15. How can I convert string to integer in golang
  16. Accessing struct fields inside a map value (without copying)
  17. Why do I get a “cannot assign” error when setting value to a struct as a value in a map? [duplicate]
  18. How to get memory size of variable in Go?
  19. Organize local code in packages using Go modules
  20. How can I pass a slice as a variadic input?
  21. Does Go provide REPL?
  22. How to compare if two structs, slices or maps are equal?
  23. Golang defer behavior
  24. Stack vs heap allocation of structs in Go, and how they relate to garbage collection
  25. What is the meaning of “dot parenthesis” syntax? [duplicate]
  26. why slice values can sometimes go stale but never map values?
  27. How to import local packages in go?
  28. How to compare Go errors
  29. How to write a generic function that accepts any numerical type?
  30. How to disable “use of internal package not allowed”

Leave a Comment