def get_complex_array(array):
    """Output a complex array from the input array.

    :param array: array that has real parts in columns 0, 2, 4,... \
                  and imaginary part in columns 1, 3, 5,...
    :return: An array with complex data type
    """
    complex_array = array[:, 0::2] + 1j * array[:, 1::2]

    return complex_array