Python – Vertical Grouping Value Lists
Sometimes, while working with Python dictionaries, we can have a problem in which we need to group all the list values vertically, i.e w.r.t similar index. This kind of problem can have applications in many domains such as web development. Let’s discuss certain ways in which this problem can be solved.
Input : test_dict = {‘Gfg’: [4, 8], ‘is’: [87, 2], ‘best’ : [14, 1]} Output : [(4, 87, 14), (8, 2, 1)] Input : test_dict = {‘Gfg’: [4, 6, 7, 8]} Output : [(4, ), (6, ), (7, ), (8, )]
Method #1 : Using list comprehension + zip() + * operator The combination of above functions can be used to solve this problem. In this, we perform the task of extracting values using values() and zip() is used to perform vertical grouping after unpacking using * operator.
Python3
# Python3 code to demonstrate working of # Vertical Grouping Value Lists# Using list comprehension + zip() + * operator# initializing dictionarytest_dict = {'Gfg': [4, 5, 7], 'is': [8, 9, 10], 'best' : [10, 12, 14]}# printing original dictionaryprint("The original dictionary is : " + str(test_dict))# Vertical Grouping Value Lists# Using list comprehension + zip() + * operatorres = [tuple(idx) for idx in zip(*test_dict.values())] # printing result print("The grouped values : " + str(res)) |
The original dictionary is : {'Gfg': [4, 5, 7], 'is': [8, 9, 10], 'best': [10, 12, 14]}
The grouped values : [(4, 8, 10), (5, 9, 12), (7, 10, 14)]
Method #2 : Using list() + zip() + values() The combination of above functions can be used to solve this problem. In this, we perform the task similar to above method, the difference being using list() instead of list comprehension.
Python3
# Python3 code to demonstrate working of # Vertical Grouping Value Lists# Using list() + zip() + values()# initializing dictionarytest_dict = {'Gfg': [4, 5, 7], 'is': [8, 9, 10], 'best' : [10, 12, 14]}# printing original dictionaryprint("The original dictionary is : " + str(test_dict))# Vertical Grouping Value Lists# Using list() + zip() + values()res = list(zip(*test_dict.values())) # printing result print("The grouped values : " + str(res)) |
The original dictionary is : {'Gfg': [4, 5, 7], 'is': [8, 9, 10], 'best': [10, 12, 14]}
The grouped values : [(4, 8, 10), (5, 9, 12), (7, 10, 14)]
Method #3 : Using nested for loops
Approach
Use nested for loops to group value list vertically
Python3
# Python3 code to demonstrate working of# Vertical Grouping Value Lists# initializing dictionarytest_dict = {'Gfg': [4, 5, 7], 'is': [8, 9, 10], 'best' : [10, 12, 14]}# printing original dictionaryprint("The original dictionary is : " + str(test_dict))# Vertical Grouping Value Listsres=[]x=list(test_dict.values())for i in range(0,len(x)): v=[] for j in range(0,len(x[i])): v.append(x[j][i]) res.append(tuple(v)) # printing resultprint("The grouped values : " + str(res)) |
The original dictionary is : {'Gfg': [4, 5, 7], 'is': [8, 9, 10], 'best': [10, 12, 14]}
The grouped values : [(4, 8, 10), (5, 9, 12), (7, 10, 14)]
Time Complexity : O(M*N) M – length of dictionary N- length of each list in value list
Auxiliary Space : O(M*N) M – length of dictionary N- length of each list in value list
