def get_param_dict(df, column_name, cast_as_type):
    """
    :param df: the project-params dataframe
    :param column_name: string, column name of the parameter to look for
    :param cast_as_type: the type for the parameter
    :return: dictionary, {project: param_value}

    Create a dictionary for the parameter to load into Pyomo.
    """
    param_dict = dict()

    for row in zip(df["project"], df[column_name]):
        [prj, param_val] = row
        # Add to the param dictionary if a value is specified
        # Otherwise, we'll use the default value (or Pyomo will throw an
        # error if no default value)
        if param_val != ".":
            param_dict[prj] = cast_as_type(row[1])
        else:
            pass

    return param_dict