Given a list of string, write a Python program to convert it into sorted list of integer.
Examples:
Input: ['21', '1', '131', '12', '15'] Output: [1, 12, 15, 21, 131] Input: ['11', '1', '58', '15', '0'] Output: [0, 1, 11, 15, 58]
Let’s discuss different methods we can achieve this task.
Method #1: Using map and sorted()
Python3
# Python code to convert list of# string into sorted list of integer# List initializationlist_string = ['21', '1', '131', '12', '15']# mappinglist_map = map(int, list_string)# sorting listlist_sorted = sorted(list_map)# Printing sorted list of integersprint(list_sorted) |
[1, 12, 15, 21, 131]
Time Complexity: O(n), where n is the length of the list
Auxiliary Space: O(n) additional space of size n is created where n is the number of elements in the list
Method #2: Using list comprehension
Python3
# Python code to convert list of # string into sorted list of integer# List initializationlist_string = ['11', '1', '58', '15', '0']# Using list comprehensionoutput = [int(x) for x in list_string]# using sort functionoutput.sort()# Printing outputprint(output) |
[0, 1, 11, 15, 58]
Method #3: Using iteration
Python3
# Python code to convert list of# string into sorted list of integer# List initializationlist_string = ['11', '1', '58', '15', '0']# using iteration and sorted()list_sorted = sorted(int(x) for x in list_string)# printing outputprint(list_sorted) |
[0, 1, 11, 15, 58]
Method: Using enumerate function
Python3
lst = ['11', '1', '58', '15', '0'];l=[]for i,a in enumerate(lst): l.append(int(a))print(sorted(l)) |
[0, 1, 11, 15, 58]
Method #: Using lambda
Python3
# Python code to convert list of# string into sorted list of integer# List initializationlist_string = ['11', '1', '58', '15', '0']# sorting listsorted_list = [int(i) for i in sorted(list_string, key=lambda x: int(x))]print(sorted_list)#This code is contributed by Edula Vinay Kumar Reddy |
[0, 1, 11, 15, 58]
The time complexity of this approach is O(n * log(n)), where n is the number of elements in the list. This is because the sorted function uses a sorting algorithm, such as quicksort or mergesort, which has a time complexity of O(n * log(n)) for sorting a list of n elements.
The space complexity of this approach is O(n), since a new list is created to store the sorted elements.
Method #: Using the sorted method and a key function
Python3
list_string = ['21', '1', '131', '12', '15']list_sorted = sorted(list_string, key=int)list_sorted = [int(x) for x in list_sorted]print(list_sorted)#This code is contributed by Vinay pinjala. |
[1, 12, 15, 21, 131]
Time Complexity: O(nlogn)
Auxiliary Space: O(n)
Method#: Using Recursive method.
Python3
# List initializationlist_string = ['21', '1', '131', '12', '15']def sort_and_convert(lst): if len(lst) <= 1: return [int(lst[0])] if lst else [] else: pivot = lst[0] left = sort_and_convert([x for x in lst[1:] if int(x) <= int(pivot)]) right = sort_and_convert([x for x in lst[1:] if int(x) > int(pivot)]) return left + [int(pivot)] + right# sorting listlist_sorted = sort_and_convert(list_string)# Printing sorted list of integersprint(list_sorted)#this code contributed by tvsk |
[1, 12, 15, 21, 131]
Time Complexity: O(n log n)
Auxiliary Space: O(n)
Method #8: Using the built-in function sorted with a key argument
This method uses the built-in sorted function and specifies the key argument as int, which tells sorted to convert each element of the list to an integer before comparing and sorting them. This results in a sorted list of integers.
Python3
list_string = ['21', '1', '131', '12', '15']list_sorted = sorted(list_string, key=int)print(list_sorted) |
['1', '12', '15', '21', '131']
Time complexity: O(n log n), where n is the length of the input list. This is because sorted uses a sorting algorithm that has a worst-case time complexity of O(n log n).
Auxiliary space: O(n), where n is the length of the input list. This is because sorted creates a new list to store the sorted elements, which has the same length as the input list.
