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Removing an Element from a Slice Items need to be removed from a slice by slicing them out. To remove an element, you must slice out the items before that element, slice out the items after that element, then append these two new slices together without the element that you wanted to remove.
How to check if a slice contains an element. To check if a particular element is present in a slice object, we need to perform the following steps: Use a for loop to iterate over each element in the slice . Use the equality operator ( == ) to check if the current element matches the element you want to find.
To add an element to a slice , you can use Golang's built-in append method. append adds elements from the end of the slice. The first parameter to the append method is a slice of type T . Any additional parameters are taken as the values to add to the given slice .
In the Go slice, you can search an element of string type in the given slice of strings with the help of SearchStrings() function. This function searches for the given element in a sorted slice of strings and returns the index of that element if present in the given slice.
Where a is the slice, and i is the index of the element you want to delete:
a = append(a[:i], a[i+1:]...)
... is syntax for variadic arguments in Go.
Basically, when defining a function it puts all the arguments that you pass into one slice of that type. By doing that, you can pass as many arguments as you want (for example, fmt.Println can take as many arguments as you want).
Now, when calling a function, ... does the opposite: it unpacks a slice and passes them as separate arguments to a variadic function.
So what this line does:
a = append(a[:0], a[1:]...)
is essentially:
a = append(a[:0], a[1], a[2])
Now, you may be wondering, why not just do
a = append(a[1:]...)
Well, the function definition of append is
func append(slice []Type, elems ...Type) []Type
So the first argument has to be a slice of the correct type, the second argument is the variadic, so we pass in an empty slice, and then unpack the rest of the slice to fill in the arguments.
There are two options:
A: You care about retaining array order:
a = append(a[:i], a[i+1:]...)
// or
a = a[:i+copy(a[i:], a[i+1:])]
B: You don't care about retaining order (this is probably faster):
a[i] = a[len(a)-1] // Replace it with the last one. CAREFUL only works if you have enough elements.
a = a[:len(a)-1] // Chop off the last one.
See the link to see implications re memory leaks if your array is of pointers.
https://github.com/golang/go/wiki/SliceTricks
Rather than thinking of the indices in the [a:]-, [:b]- and [a:b]-notations as element indices, think of them as the indices of the gaps around and between the elements, starting with gap indexed 0 before the element indexed as 0.
Looking at just the blue numbers, it's much easier to see what is going on: [0:3] encloses everything, [3:3] is empty and [1:2] would yield {"B"}. Then [a:] is just the short version of [a:len(arrayOrSlice)], [:b] the short version of [0:b] and [:] the short version of [0:len(arrayOrSlice)]. The latter is commonly used to turn an array into a slice when needed.
... is syntax for variadic arguments.
I think it is implemented by the complier using slice ([]Type), just like the function append :
func append(slice []Type, elems ...Type) []Type
when you use "elems" in "append", actually it is a slice([]type).
So "a = append(a[:0], a[1:]...)" means "a = append(a[0:0], a[1:])"
a[0:0] is a slice which has nothing
a[1:] is "Hello2 Hello3"
This is how it works
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