# one

one(x)

Get the multiplicative identity element for the type of `x` (`x` can also specify the type itself). For matrices, returns an identity matrix of the appropriate size and type.

## Examples

``````julia> one(10)
1
julia> foo = zeros(Int8, (2,2));
julia> one(foo)
2x2 Array{Int8,2}:
1  0
0  1
julia> complexNumber = complex(1, 1);   # 1 + 1im
julia> one(complexNumber)
1 + 0im``````
1. Get the multiplicative identity element for a numeric type:

``````julia> one(3)
1

julia> one(3.5)
1.0``````

In this example, `one` returns the multiplicative identity element for the given numeric values.

2. Get the multiplicative identity element for a custom type:

``````julia> struct MyType end

julia> one(MyType())
MyType()``````

Here, `one` returns the multiplicative identity element for a custom type `MyType`.

3. Get the identity matrix for a matrix type:

``````julia> A = [1 2; 3 4];

julia> one(A)
2×2 Matrix{Int64}:
1  0
0  1``````

When given a matrix `A`, `one` returns an identity matrix of the appropriate size and type.

Common mistake example:

``````julia> one("abc")
ERROR: MethodError: no method matching one(::String)``````

In this example, `one` is called with a string argument. However, `one` is not defined for strings, so it raises a `MethodError`. It's important to note that `one` is typically used with numeric types or matrices.