Given a list, the task is to create a new list containing difference of adjacent elements in the given list.
Method #1: Using zip()
Python3
# Python code to demonstrate# to calculate difference# between adjacent elements in list# initialising _listini_list = [5, 4, 89, 12, 32, 45]# printing iniial_listprint("intial_list", str(ini_list))# Calculating difference listdiff_list = []for x, y in zip(ini_list[0::], ini_list[1::]): diff_list.append(y-x) # printing difference listprint ("difference list: ", str(diff_list)) |
intial_list [5, 4, 89, 12, 32, 45] difference list: [-1, 85, -77, 20, 13]
Time Complexity: O(n), where n is the length of the list ini_list
Auxiliary Space: O(n) additional space of size n is created where n is the number of elements in the diff list
Method #2: Using Naive approach
Python3
# Python code to demonstrate# to calculate difference# between adjacent elements in list# initialising _listini_list = [5, 4, 89, 12, 32, 45]# printing iniial_listprint("intial_list", str(ini_list))# Calculating difference listdiff_list = []for i in range(1, len(ini_list)): diff_list.append(ini_list[i] - ini_list[i-1])# printing difference listprint ("difference list: ", str(diff_list)) |
intial_list [5, 4, 89, 12, 32, 45] difference list: [-1, 85, -77, 20, 13]
Method #3: Using numpy
Python3
# Python code to demonstrate# to calculate difference# between adjacent elements in listimport numpy as np# initialising _listini_list = np.array([5, 4, 89, 12, 32, 45])# printing iniial_listprint("intial_list", str(ini_list))# Calculating difference listdiff_list = np.diff(ini_list)# printing difference listprint ("difference list: ", str(diff_list)) |
intial_list [ 5 4 89 12 32 45] difference list: [ -1 85 -77 20 13]
Method #4: Using list comprehension(one liner)
To calculate the difference between adjacent elements in a list using list comprehension, you can use the following approach:
Python3
# initializing the listini_list = [5, 4, 89, 12, 32, 45]# using list comprehension to calculate the difference between adjacent elementsdiff_list = [ini_list[i+1] - ini_list[i] for i in range(len(ini_list)-1)]# printing the difference listprint(diff_list)#This code is contributed by Edula Vinay Kumar Reddy |
[-1, 85, -77, 20, 13]
Time complexity: O(n)
Auxiliary Space: O(n)
Using map and lambda:
Approach:
lst[:-1] returns [5, 4, 89, 12, 32], which is lst with the last element removed.
lst[1:] returns [4, 89, 12, 32, 45], which is lst with the first element removed.
The lambda x, y: y – x function takes two arguments x and y and returns their difference y – x.
map(lambda x, y: y – x, lst[:-1], lst[1:]) applies the lambda function to corresponding elements from lst[:-1] and lst[1:], resulting in an iterator object of the form <map object at 0x…>.
list(map(lambda x, y: y – x, lst[:-1], lst[1:])) converts the iterator object to a list, which is the output of diff_adjacent_elements_3.
The resulting list is [-1, 85, -77, 20, 13], which is the difference between adjacent elements in the input list [5, 4, 89, 12, 32, 45].
Python3
def diff_adjacent_elements_3(lst): return list(map(lambda x, y: y - x, lst[:-1], lst[1:]))initial_list = [5, 4, 89, 12, 32, 45]diff_list = diff_adjacent_elements_3(initial_list)print(f"Input list: {initial_list}")print(f"Difference list: {diff_list}") |
Input list: [5, 4, 89, 12, 32, 45] Difference list: [-1, 85, -77, 20, 13]
Time Complexity: O(n)
Auxiliary Space: O(n)
