你如何製作價值對並重復它們？

Question

def cartesian_product(table1, table2): 

    '''(table, table) -> table 

    Return a table that is created by joining the tables table1 and table2. The 
    cartesian products of the two tables is a new table where each row in the first 
    table is paired with every row in the second table. Each table is supposed to 
    be a dictionary. 

    Example: 

    dict1 = {'a': ['b', 'c']} 
    dict2 = {'d': ['e', 'f']} 
    cartesian_product({'a': ['b', 'c']}, {'d': ['e', 'f']}) 
    {'a': ['b', 'b', 'c', 'c'], 'd': ['e', 'f', 'e', 'f']} 

    ''' 

    table1 = list(table1.values()) 
    table2 = list(table2.values()) 

    for object1 in table1: 
     x = object1 

     for object2 in table2: 
      y = object2 

      return x,y 

這是我到目前爲止，我知道的輸出是：

(['b', 'c'], ['e', 'f']) 

我想它返回：

{'a': ['b', 'b', 'c', 'c'], 'd': ['e', 'f', 'e', 'f']} 

我可以嘗試返回字典自己 - 但在列表中 - 你如何配對並重復它們？

Answer 1

使用itertools.product()生產對，然後你就可以添加到您的輸出：

from itertools import product 

def cartesian_product(table1, table2): 
    (table1_name, table1_columns), = table1.items() 
    (table2_name, table2_columns), = table2.items() 
    output = {table1_name: [], table2_name: []} 
    for cola, colb in product(table1_columns, table2_columns): 
     output[table1_name].append(cola) 
     output[table2_name].append(colb) 
    return output 

，或者你可以嵌套循環：

def cartesian_product(table1, table2): 
    (table1_name, table1_columns), = table1.items() 
    (table2_name, table2_columns), = table2.items() 
    output = {table1_name: [], table2_name: []} 
    for cola in table1_columns: 
     for colb in table2_columns: 
      output[table1_name].append(cola) 
      output[table2_name].append(colb) 
    return output