Python – Maximum available value Dictionaries

Given list of dictionaries and a list, extract all the dictionaries which contain maximum available value of key from list.

Input : test_list [{“Gfg” : 6, “is” : 9, “best” : 10}, {“Gfg” : 8, “is” : 11, “best” : 19}, {“Gfg” : 2, “is” : 16, “best” : 10}], K = “best”, arg_list = [10, 7, 6, 12] Output : [{‘Gfg’: 6, ‘is’: 9, ‘best’: 10}, {‘Gfg’: 2, ‘is’: 16, ‘best’: 10}] Explanation : Maximum available value of “best” is 19, but not present in list, hence next max. is 10, all dictionaries corresponding are returned. Input : test_list [{“Gfg” : 6, “is” : 9, “best” : 10}, {“Gfg” : 8, “is” : 11, “best” : 19}], K = “Gfg”, arg_list = [10, 7, 6, 12] Output : [{‘Gfg’: 6, ‘is’: 9, ‘best’: 10}] Explanation : Maximum value present in this case is 6, hence returned.

Method #1 : Using loop

This is brute way in which this problem can be solved. In this, first maximum value is obtained from dictionary values, which is also present in provided list. Post that all the dictionaries, which have that value are extracted.

Python3

# Python3 code to demonstrate working of
# Maximum available value Dictionaries
# Using loop

# initializing lists
test_list = [{"Gfg" : 6, "is" : 9, "best" : 10},
             {"Gfg" : 8, "is" : 11, "best" : 19},
             {"Gfg" : 2, "is" : 16, "best" : 10},
             {"Gfg" : 12, "is" : 1, "best" : 8},
             {"Gfg" : 22, "is" : 6, "best" : 8}]

# printing original list
print("The original list : " + str(test_list))

# initializing K
K = "best"

# initializing list
arg_list = [10, 7, 6, 12]

# extracting value to find from dictionary
# corresponding to key
max_ele = 0
for sub in test_list:
    if sub[K] in arg_list:

        # maximum of all possible present for a key
        max_ele = max(sub[K], max_ele)

# extracting dictionary with maximum and present value of key
res = [sub for sub in test_list if sub[K] == max_ele]

# printing result
print("The extracted dictionaries : " + str(res))

Output

The original list : [{‘Gfg’: 6, ‘is’: 9, ‘best’: 10}, {‘Gfg’: 8, ‘is’: 11, ‘best’: 19}, {‘Gfg’: 2, ‘is’: 16, ‘best’: 10}, {‘Gfg’: 12, ‘is’: 1, ‘best’: 8}, {‘Gfg’: 22, ‘is’: 6, ‘best’: 8}] The extracted dictionaries : [{‘Gfg’: 6, ‘is’: 9, ‘best’: 10}, {‘Gfg’: 2, ‘is’: 16, ‘best’: 10}]

Time Complexity: O(n), where n is the values in dictionary
Auxiliary Space: O(n), where n is the size of dictionary

Method #2: Using list comprehension and built-in functions

Python3

# Python3 code to demonstrate working of
# Maximum available value Dictionaries
# Using list comprehension and built-in functions

# initializing list of dictionaries and key to find maximum value for
test_list = [{"Gfg" : 6, "is" : 9, "best" : 10},
             {"Gfg" : 8, "is" : 11, "best" : 19},
             {"Gfg" : 2, "is" : 16, "best" : 10},
             {"Gfg" : 12, "is" : 1, "best" : 8},
             {"Gfg" : 22, "is" : 6, "best" : 8}]
K = "best"

# extracting values to find from dictionary corresponding to key
arg_list = [10, 7, 6, 12]
values_to_find = set(arg_list)

# filtering list of dictionaries to only include those with a value in the values_to_find set
filtered_list = [d for d in test_list if d[K] in values_to_find]

# finding maximum value of key in the filtered list of dictionaries
max_value = max(d[K] for d in filtered_list)

# filtering list of dictionaries to only include those with the maximum value for the key
result_list = [d for d in filtered_list if d[K] == max_value]

# printing original list, extracted dictionaries, and maximum value
print("The original list : " + str(test_list))
print("The extracted dictionaries : " + str(result_list))
print("The maximum value of key '" + K + "' is: " + str(max_value))

Output

The original list : [{'Gfg': 6, 'is': 9, 'best': 10}, {'Gfg': 8, 'is': 11, 'best': 19}, {'Gfg': 2, 'is': 16, 'best': 10}, {'Gfg': 12, 'is': 1, 'best': 8}, {'Gfg': 22, 'is': 6, 'best': 8}]
The extracted dictionaries : [{'Gfg': 6, 'is': 9, 'best': 10}, {'Gfg': 2, 'is': 16, 'best': 10}]
The maximum value of key 'best' is: 10

Time complexity: O(n), where n is the length of the list of dictionaries. 

Auxiliary space: O(n), where n is the length of the list of dictionaries.