Given a list of elements, and percent ranges, the task is to write a python program to extract all the elements whose frequency is present in a given range.
Input : test_list = [4, 6, 2, 4, 6, 7, 8, 4, 9, 1, 4, 6, 7, 8], strt, end = 13, 25
Output : [6, 7, 8]
Explanation : 21.4, 14.2, 14.2 is percentage presence of 6, 7, 8 respectively.
Input : test_list = [4, 6, 2, 4, 6, 7, 8, 4, 9, 1, 4, 6, 7, 8], strt, end = 13, 20
Output : [7, 8]
Explanation : 14.2, 14.2 is percentage presence of 7, 8 respectively.
Presence percentage can be simply computed by the below formula:
Frequency of the element present in the list/ total no. of elements in the list
Method #1 : Using Counter() + set() + loop + len()
In this, frequencies of all the elements are extracted using loop. Next step is to get the set of elements of list and check if frequencies are between range specified.
Python3
# Python3 code to demonstrate working of# Element frequencies in percent range# Using Counter() + set() + loop + len()from collections import Counter# initializing listtest_list = [4, 6, 2, 4, 6, 7, 8, 4, 9, 1, 4, 6, 7, 8]# printing original listprint("The original list is : " + str(test_list))# initializing percent rangesstrt, end = 13, 25# getting frequenciesfreqs = dict(Counter(test_list))# computing percents and assigningres = []for ele in set(test_list): percent = (freqs[ele] / len(test_list)) * 100 if percent >= strt and percent <= end: res.append(ele)# printing resultprint("Elements within range of frequencies : " + str(res)) |
Output:
The original list is : [4, 6, 2, 4, 6, 7, 8, 4, 9, 1, 4, 6, 7, 8] Elements within range of frequencies : [6, 7, 8]
Time Complexity: O(n)
Auxiliary Space: O(n)
Method #2 : Using Counter() + loop + len()
This performs tasks in an almost similar manner, the key difference being the Counter keys are iterated rather than the list elements, as they’d provide similar output.
Python3
# Python3 code to demonstrate working of# Element frequencies in percent range# Using Counter() + loop + len()from collections import Counter# initializing listtest_list = [4, 6, 2, 4, 6, 7, 8, 4, 9, 1, 4, 6, 7, 8]# printing original listprint("The original list is : " + str(test_list))# initializing percent rangesstrt, end = 13, 25# getting frequenciesfreqs = dict(Counter(test_list))# computing percents and assigning# iterating from dictionaryres = []for ele in freqs: percent = (freqs[ele] / len(test_list)) * 100 if percent >= strt and percent <= end: res.append(ele)# printing resultprint("Elements within range of frequencies : " + str(res)) |
Output:
The original list is : [4, 6, 2, 4, 6, 7, 8, 4, 9, 1, 4, 6, 7, 8] Elements within range of frequencies : [6, 7, 8]
Time complexity: O(n*n), where n is the length of the test_list. The Counter() + loop + len() takes O(n*n) time
Auxiliary Space: O(n), extra space of size n is required
