Python – 选择性元组键的产物

有时，在使用元组列表时，我们会遇到一个问题，即我们有特定的键列表，我们只需要元组列表中这些键的值的乘积。这在特定实体的评级或产品中具有实用性。让我们讨论一些可以做到这一点的方法。

方法 #1：使用dict() + loop + get() + list comprehension
我们可以通过首先将列表转换为字典然后使用列表推导来使用 get函数获取特定键的值来执行此特定任务。使用循环执行值的乘积。

# Python3 code to demonstrate 
# Product of Selective Tuple Keys
# using dict() + get() + list comprehension + loop
  
# getting Product 
def prod(val) : 
    res = 1 
    for ele in val: 
        res *= ele 
    return res  
  
# initializing list of tuples 
test_list = [('Nikhil', 1), ('Akash', 2), ('Akshat', 3), ('Manjeet', 4)]
  
# initializing selection list 
select_list = ['Nikhil', 'Akshat']
  
# printing original list 
print ("The original list is : " + str(test_list))
  
# printing selection list 
print ("The selection list is : " + str(select_list))
  
# using dict() + get() + list comprehension + loop
# Product of Selective Tuple Keys
temp = dict(test_list)
res = prod([temp.get(i, 0) for i in select_list])
  
# printing result
print ("The selective values product of keys : " + str(res))

输出 ：

The original list is : [('Nikhil', 1), ('Akash', 2), ('Akshat', 3), ('Manjeet', 4)]
The selection list is : ['Nikhil', 'Akshat']
The selective values product of keys : 3

方法 #2：使用next() + loop + 列表推导
这个特定问题可以使用下一个函数来解决，该函数使用迭代器执行迭代，因此可以更有效地实现可能的解决方案。使用循环执行值的乘积。

# Python3 code to demonstrate 
# Product of Selective Tuple Keys
# using next() + list comprehension + loop
  
# getting Product 
def prod(val) : 
    res = 1 
    for ele in val: 
        res *= ele 
    return res  
  
# initializing list of tuples 
test_list = [('Nikhil', 1), ('Akash', 2), ('Akshat', 3), ('Manjeet', 4)]
  
# initializing selection list 
select_list = ['Nikhil', 'Akshat']
  
# printing original list 
print ("The original list is : " + str(test_list))
  
# printing selection list 
print ("The selection list is : " + str(select_list))
  
# using next() + list comprehension + loop
# Product of Selective Tuple Keys
res = prod([next((sub[1] for sub in test_list if sub[0] == i), 0) for i in select_list])
  
# printing result
print ("The selective values product of keys : " + str(res))

输出 ：

The original list is : [('Nikhil', 1), ('Akash', 2), ('Akshat', 3), ('Manjeet', 4)]
The selection list is : ['Nikhil', 'Akshat']
The selective values product of keys : 3