Python – 切片直到 K 字典值列表

给定具有值作为列表的字典，将每个列表切片直到 K。

Input : test_dict = {“Gfg” : [1, 6, 3, 5, 7], “Best” : [5, 4, 2, 8, 9], “is” : [4, 6, 8, 4, 2]}, K = 3
Output : {‘Gfg’: [1, 6, 3], ‘Best’: [5, 4, 2], ‘is’: [4, 6, 8]}
Explanation : The extracted 3 length dictionary value list.

Input : test_dict = {“Gfg” : [1, 6, 3, 5, 7], “Best” : [5, 4, 2, 8, 9], “is” : [4, 6, 8, 4, 2]}, K = 2
Output : {‘Gfg’: [1, 6], ‘Best’: [5, 4], ‘is’: [4, 6]}
Explanation : The extracted 2 length dictionary value list.

方法#1：使用循环+列表切片

上述功能的组合可以用来解决这个问题。在此，我们使用切片操作执行列表切片任务并循环遍历所有键。

Python3

# Python3 code to demonstrate working of 
# Slice till K dictionary value lists
# Using loop + list slicing 
  
# initializing dictionary
test_dict = {"Gfg" : [1, 6, 3, 5, 7], 
             "Best" : [5, 4, 2, 8, 9],
             "is" : [4, 6, 8, 4, 2]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# initializing K 
K = 4
  
res = dict()
for sub in test_dict:
      
    # slicing till K and reassigning
    res[sub] = test_dict[sub][:K]
  
# printing result 
print("The dictionary after conversion " + str(res))

输出

The original dictionary is : {‘Gfg’: [1, 6, 3, 5, 7], ‘Best’: [5, 4, 2, 8, 9], ‘is’: [4, 6, 8, 4, 2]}
The dictionary after conversion {‘Gfg’: [1, 6, 3, 5], ‘Best’: [5, 4, 2, 8], ‘is’: [4, 6, 8, 4]}

方法#2：使用字典理解+列表切片

这是可以执行此任务的另一种方式。在此，我们使用字典理解执行重新分配的任务，并为这个问题提供了一种线性方法。

Python3

# Python3 code to demonstrate working of 
# Slice till K dictionary value lists
# Using dictionary comprehension + list slicing
  
# initializing dictionary
test_dict = {"Gfg" : [1, 6, 3, 5, 7],
             "Best" : [5, 4, 2, 8, 9], 
             "is" : [4, 6, 8, 4, 2]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# initializing K 
K = 4
  
# one-liner to slice elements of list 
# items() used to get all key-value pair of dictionary
res = {key: val[:K] for key, val in test_dict.items()}
  
# printing result 
print("The dictionary after conversion " + str(res)) 

输出

The original dictionary is : {‘Gfg’: [1, 6, 3, 5, 7], ‘Best’: [5, 4, 2, 8, 9], ‘is’: [4, 6, 8, 4, 2]}
The dictionary after conversion {‘Gfg’: [1, 6, 3, 5], ‘Best’: [5, 4, 2, 8], ‘is’: [4, 6, 8, 4]}