map!(f,collection)

``````..  map!(function, collection)

In-place version of :func:`map`.``````

Examples

``````julia> foo = [1   2   3];
julia> map!((x) -> x^3, foo);
julia> foo
1x3 Array{Int64,2}:
1      8       27``````

Passing destination as a param

``````julia> function F(x,y)
x^2+y^2
end
julia> bar = Array(Int64,1,3);
julia> map!(F,   bar,    [3    6   12],   [4   8   5])
1x3 Array{Int64,2}:
25    100     169``````
``````julia> A = [1, 2, 3, 4];
julia> B = similar(A);
julia> map!(x -> x^2, B, A)
4-element Array{Int64,1}:
1
4
9
16``````

In this example, the `map!` function applies the provided function `x -> x^2` element-wise to the collection `A`, and stores the result in the preallocated array `B`, which is created using the `similar` function to match the size and element type of `A`. The resulting array `B` contains the squared values of the elements in `A`.

Note that `destination` (in this case, `B`) must be at least as large as the first collection (`A`) to store the mapped values.