Example
If you need to remove one or more elements from a slice, or if you need to work with a sub slice of another existing one; you can use the following method.
Following examples uses slice of int, but that works with all type of slice.
So for that, we need a slice, from witch we will remove some elements:
slice := []int{1, 2, 3, 4, 5, 6}
// > [1 2 3 4 5 6]
We need also the indexes of elements to remove:
// index of first element to remove (corresponding to the '3' in the slice)
var first = 2
// index of last element to remove (corresponding to the '5' in the slice)
var last = 4
And so we can "slice" the slice, removing undesired elements:
// keeping elements from start to 'first element to remove' (not keeping first to remove),
// removing elements from 'first element to remove' to 'last element to remove'
// and keeping all others elements to the end of the slice
newSlice1 := append(slice[:first], slice[last+1:]...)
// > [1 2 6]
// you can do using directly numbers instead of variables
newSlice2 := append(slice[:2], slice[5:]...)
// > [1 2 6]
// Another way to do the same
newSlice3 := slice[:first + copy(slice[first:], slice[last+1:])]
// > [1 2 6]
// same that newSlice3 with hard coded indexes (without use of variables)
newSlice4 := slice[:2 + copy(slice[2:], slice[5:])]
// > [1 2 6]
To remove only one element, just have to put the index of this element as the first AND as the last index to remove, just like that:
var indexToRemove = 3
newSlice5 := append(slice[:indexToRemove], slice[indexToRemove+1:]...)
// > [1 2 3 5 6]
// hard-coded version:
newSlice5 := append(slice[:3], slice[4:]...)
// > [1 2 3 5 6]
And you can also remove elements from the beginning of the slice:
newSlice6 := append(slice[:0], slice[last+1:]...)
// > [6]
// That can be simplified into
newSlice6 := slice[last+1:]
// > [6]
You can also removing some elements from the end of the slice:
newSlice7 := append(slice[:first], slice[first+1:len(slice)-1]...)
// > [1 2]
// That can be simplified into
newSlice7 := slice[:first]
// > [1 2]
If the new slice have to contains exactly the same elements than the first one, you can use the same thing but with
last := first-1.
(This can be useful in case of your indexes are previously computed)
