<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def sub_dfs_by_num(df, num):
 """Get a generator yielding num consecutive sub-dataframes of the given df. Arguments --------- df : pandas.DataFrame The dataframe for which to get sub-dataframes. num : int The number of sub-dataframe to divide the given dataframe into. Returns ------- generator A generator yielding n consecutive sub-dataframes of the given df. Example ------- age name 0 23 Jen 1 42 Ray age name 2 15 Fin """

    size = len(df) / float(num)
    for i in range(num):
        yield df.iloc[int(round(size * i)): int(round(size * (i + 1)))]