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prepend!

prepend!(collection, items) -> collection

Insert the elements of items to the beginning of collection.

julia> prepend!([3],[1,2])
3-element Array{Int64,1}:
 1
 2
 3

Examples

1. Prepend elements to an array:

   julia> arr = [3];
   julia> prepend!(arr, [1, 2])
   3-element Array{Int64,1}:
   1
   2
   3

   This example adds the elements [1, 2] to the beginning of the array arr.

2. Prepend elements to a vector of strings:

   julia> words = ["orange", "apple"];
   julia> prepend!(words, ["grape", "banana"])
   4-element Array{String,1}:
   "grape"
   "banana"
   "orange"
   "apple"

   It adds the elements ["grape", "banana"] to the beginning of the vector of strings.

3. Handle edge cases when prepending to an empty collection:

   julia> numbers = Int64[];
   julia> prepend!(numbers, [1, 2, 3])
   3-element Array{Int64,1}:
   1
   2
   3

   It correctly handles the case where the collection is initially empty.

Common mistake example:

julia> arr = [5, 10, 15, 20];
julia> prepend!(arr, 7)
ERROR: MethodError: no method matching prepend!(::Array{Int64,1}, ::Int64)

In this example, a single element (7) is passed instead of a collection of elements. The prepend! function expects a collection as the second argument. Make sure to provide a collection (e.g., an array or vector) when using prepend!.

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