Python Lists are a type of data structure that is mutable in nature. This means that we can modify the elements in the list. We can sort a list in Python using the inbuilt list sort() function. But in this article, we will learn how we can sort a list in a particular order without using the list sort() method.
Sort a List Without Using Sort Function in Python
Sorting is nothing but arranging the elements of a list in a particular order and this order can be either increasing or decreasing in nature. We can sort a list in Python without using the list sort() function by using nested for loops. Let us see a few examples, of how we can sort a list without the sort() function.
Sort a List in Ascending Order Without using an Extra Variable
In this example, we will have a list and we will sort it in ascending order using just the nested loop. We will compare each element in the list one by one and swap it.
Python3
#Python program to print a list # without using the sort() function# without an extra variablel1=[76, 23, 45, 12, 54, 9] print("Original List:", l1)# sorting list using nested loopsfor i in range(0, len(l1)): for j in range(i+1, len(l1)): if l1[i] >= l1[j]: l1[i], l1[j] = l1[j],l1[i]# sorted listprint("Sorted List", l1) |
Output:
Original List: [76, 23, 45, 12, 54, 9]
Sorted List [9, 12, 23, 45, 54, 76]
Sort a List in Ascending Order by Using an extra variable
In this example, we will have a list and we will sort it in ascending order by using the nested for loop and a temporary variable.
Python3
#Python program to print a list # without using the sort() function# using an extra variablel1=[76,23,45,12,54,9] print("Original List:", l1)# sorting list using nested loopsfor i in range(0, len(l1)): for j in range(i+1, len(l1)): if l1[i] >= l1[j]: # temporary variable temp = l1[i] l1[i] = l1[j] l1[j] = temp# sorted listprint("Sorted List", l1) |
Output:
Original List: [76, 23, 45, 12, 54, 9]
Sorted List [9, 12, 23, 45, 54, 76]
Sort a List in Descending Order
In this example, instead of a predefined list, we will take a list whose values are provided by the user. Then we will sort the list in descending order without using an extra variable.
Python3
# create an empty listl1 = []n = int(input("enter number of elements required: "))# creating a list using loopfor i in range(0, n): element = int(input()) # appending elements to the list l1.append(element)print("Original List:", l1)# sorting in decendingfor i in range(0, len(l1)): for j in range(i+1, len(l1)): if l1[i] <= l1[j]: l1[i], l1[j] = l1[j], l1[i] # sorted listprint("Sorted List", l1) |
Output:
enter number of elements required: 6
76
23
45
12
54
9
Original List: [76, 23, 45, 12, 54, 9]
Sorted List [76, 54, 45, 23, 12, 9]
