Sort the values of first list using second list in Python
Given two lists, sort the values of one list using the second list.
Examples:
Input : list1 = ["a", "b", "c", "d", "e", "f", "g", "h", "i"]
list2 = [ 0, 1, 1, 0, 1, 2, 2, 0, 1]
Output :['a', 'd', 'h', 'b', 'c', 'e', 'i', 'f', 'g']
Input : list1 = ["g", "e", "e", "k", "s", "f", "o", "r", "g", "e", "e", "k", "s"]
list2 = [ 0, 1, 1, 0, 1, 2, 2, 0, 1]
Output : ['g', 'k', 'r', 'e', 'e', 'g', 's', 'f', 'o']
Approach :
- Zip the two lists.
- Create a new, sorted list based on the zip using sorted().
- Using a list comprehension extract the first elements of each pair from the sorted, zipped list.
Concept :
The purpose of zip() is to map a similar index of multiple containers so that they can be used just using as a single entity.
Below is the implementation of the above approach:
Python
# Python program to sort# one list using# the other listdef sort_list(list1, list2): zipped_pairs = zip(list2, list1) z = [x for _, x in sorted(zipped_pairs)] return z # driver codex = ["a", "b", "c", "d", "e", "f", "g", "h", "i"]y = [ 0, 1, 1, 0, 1, 2, 2, 0, 1]print(sort_list(x, y))x = ["g", "e", "e", "k", "s", "f", "o", "r", "g", "e", "e", "k", "s"]y = [ 0, 1, 1, 0, 1, 2, 2, 0, 1]print(sort_list(x, y)) |
Output:
['a', 'd', 'h', 'b', 'c', 'e', 'i', 'f', 'g'] ['g', 'k', 'r', 'e', 'e', 'g', 's', 'f', 'o']
In the above code, we have two lists, the first list is being sorted with respect to the values of the second list.
y = [ 0, 1, 1, 0, 1, 2, 2, 0, 1]
Here first the lowest value is checked. Like in this list, 0 is the lowest, so starting from the first index, 0 is the lowest and it is at index 0. So the value of index 0 is stored at index 0 in the first list. Similarly, 0 is again found at index 3 and so the value of index 3 in the first list is index 1. The same goes until the list is not completed.
Approach 2: By using Dictionary, list comprehension, lambda function
Python3
def sorting_of_element(list1,list2): # initializing blank dictionary f_1 = {} # initializing blank list final_list = [] # Addition of two list in one dictionary f_1 = {list1[i]: list2[i] for i in range(len(list2))} # sorting of dictionary based on value f_lst = {k: v for k, v in sorted(f_1.items(), key=lambda item: item[1])} # Element addition in the list for i in f_lst.keys(): final_list.append(i) return final_list list1 = ["a", "b", "c", "d", "e", "f", "g", "h", "i"]list2 = [ 0, 1, 1, 0, 1, 2, 2, 0, 1]list3=sorting_of_element(list1,list2)print(list3) |
Output:
['a', 'd', 'h', 'b', 'c', 'e', 'i', 'f', 'g']
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