# complex

complex(r, [i])

Convert real numbers or arrays to complex. `i` defaults to zero.

## Examples

1. Create a complex number from real values:

``````julia> complex(2, 3)
2 + 3im``````

This example creates a complex number with a real part of 2 and an imaginary part of 3.

2. Create a complex number with only a real part:

``````julia> complex(4)
4 + 0im``````

When only one argument is provided, the function assumes the imaginary part is zero.

3. Convert an array of real numbers to an array of complex numbers:
``````julia> real_nums = [1, 2, 3, 4];
julia> complex(real_nums)
4-element Array{Complex{Int64},1}:
1 + 0im
2 + 0im
3 + 0im
4 + 0im``````

The function can also convert an array of real numbers to an array of complex numbers.

Common mistake example:

``````julia> complex([1, 2, 3], [4, 5])
ERROR: MethodError: no method matching complex(::Array{Int64,1}, ::Array{Int64,1})``````

In this example, the `complex` function expects the second argument to be optional or a single value. Providing an array as the second argument will result in a `MethodError`. Make sure to provide a single value or omit the second argument when using `complex`.