Python cumulative sum list comprehension

Jun 17, 2020 · this part of your code [sum(lists[0:x:1]) for x in range(0, length+1)] creates a new list starting from the first element of lists up to (and excluding) the x'th element of your list (see e. Python’s reduce() is popular among developers with a functional programming background, but Python has more to offer. Then I am iterating over this set inside dictionary comprehension to get the sum of values per key. Aug 9, 2012 · total = [] for list in lists: total = listAdd(total, list) yield total. Amber. sum += i. Now to do the three adjectives using a list comprehension, the basics of a list comprehension is you give it a name. edited Sep 30, 2016 at 19:48. >>> sum([number * number for number in range(1000)]) 332833500. Following Python code demonstrates the process: f = lambda x, y: x+y. amount for v in ob. Aug 18, 2015 · count += 1. The auxiliary space complexity of the code is O (m), where m is the number of columns in the input list. I believe that A is a matrix and that X is a vector. Python programming language is a high-level and object-oriented programming language. i have the code to do basic calculator functions and now want to learn how to get the calculator to be able to do multiple problems at once with the previous answer ex. In cumulative sum, the length of returned series is same as input and every element is equal to sum of all previous elements. then it takes the sum over it. list comprehension should be used only for generating a list. Obviously avoiding the column name list at the top of the list and also the states' names. The default (None) is to compute the cumsum over the flattened array. The transposition is the essential part of the solution. The accumulate() function in Python’s itertools module provides an elegant and concise way to compute prefix sums. The most straightforward method to sum a list of integers in Python is by using the built-in sum() function. Taohidul Islam. Jan 15, 2024 · Note: Cumulative sum = sum of itself + all previous numbers in the said list. Reveal Hint Use a list comprehension to list the positive integers less than or equal to 20 that are divisible by either 3 or 5. Desired output: Adding 2 elements using lambda in Python is straight forward. list comprehension is simply a shorter syntax for a for loop which appends elements to a new list. 5. Mar 6, 2024 · Method 3: Using List Comprehension with the sum() Function. Sep 5, 2022 · Until Python 3. Length of subset is not equal. We declare an empty list cum_list to which we will append elements to form the cumulative sum list. A list comprehension should be used. cumsum #. Sep 18, 2023 · Here, we will take a list of input from the user and return the list of cumulative sum of elements of the list. The general idea of emulate sum() using a list comprehension goes against the whole purpose of a list comprehension. Step by step approach : Initialize a list of tuples test_list with three tuples containing two, three, and two elements, respectively. Mar 7, 2024 · Method 2: List Comprehension and Sum. For example, [x**2 for x in range(10)] creates a list of the squares of the numbers 0 through 9. Apr 19, 2021 · Python Program to Find the Cumulative Sum of a List where the ith Element is the Sum of the First i 1 Elements From The Original List - When it is required to find the sum of a list where the specific element is sum of first few elements, a method is defined, that takes list as parameter. It takes an iterable as an argument and returns the sum of all its elements. test_data = [5, 4, 3, 2, 1] def commulative_sum(a_list: list[int]): # The same thing you wrote. I suggest you break it down to a regular for loop, and also check and print what each expression does. sum = f(2, 9) print(sum) Output: 11. The value of start defaults to 0 an int mainly because the most common case of summation is arithmetic. Method 4: NumPy’s cumsum. reduce() is useful when you need to apply a function to an iterable and reduce it to a single cumulative value. summed=[] den_list = map(int,den_list) for i,j in enumerate(den_list[:-1]): summed += j,sum(den_list[i+1:]) If you don't want to keep the original values in the list. Jul 20, 2020 · 11 1 3. Initialize the splitter character spl_char and print it. Apr 5, 2023 · The Cumulative column sum is : [8, 15, 17] The time complexity of the given Python code is O (n), where n is the number of elements in the input list. 6. So, get rid of those first: numbers = [row[1:] for row in data[1:]] sum of the data elements [columnwise] So the first thing we need to do is transpose the data to swap columns and rows, and then we can sum each row. Apr 18, 2024 · Python - List comprehension vs map function. Method#4: Using the reduce function from the functools module: The reduce function applies the given function to the elements of lst in a cumulative manner, starting with an initial accumulator value of 0. Python3. Pythonic and compact. summed=[sum(num_list[i+1:])for i,j in enumerate(num_list[:-1])] Jan 15, 2020 · List comprehensions in Python let you create a list declaratively, much like the way you would describe the set in English. When your method is invoked after wards, you need to take a sum of last element of your temp list and first element of the original list that is now modified. Nov 5, 2015 · However, If you enter a list [] it is simply going to join the elements of a together and result in the flattened list we know and love. accumulate generator function was designed for. append(sum(a[:i+1])) print(b) OR you may use list comprehension: b = [sum(a[:x+1]) for x in range(0,len(a))] Output [4,10,22] Jul 3, 2023 · Python program to find Cumulative sum of a list. Write a program to input a list of number and then create another list from this list that contains cumulative sum of numbers in list1. 519k 84 633 555. Write a function cum_sum (somelist= []) to return cumulative sum of a numerical list or None if the list is empty. Then, flatten the list, and finally, use its length as the sum. Also, you might want to iterate over the actual list, to make things simpler. 00:00 In this tutorial, I’m going to talk about list comprehensions. i want the user to be able to do as many problems with As an alternative in just one single list comprehension, you could do: Summing list of lists with another list of lists in Python. Starting from 1st element. Accept the values into the list using another for loop and insert into the list. Also, the question/top answer have 2 million views but very few upvotes in comparison to other popular questions (that have 10x the upvotes!). Learn Data Science with. You can simply use sum(l). Here’s an example: Apr 15, 2023 · Explanation : 2 occurs 2 times in row 1 and so on. Python List Slicing). The code is written in a much easier-to-read format. lst1 += [ sum ] Q. i. Method #2 : Using zip () + map () + sum () People seem to often discount the function solution in Python, simply because the language is so expressive and allows things like list comprehensions to do a lot of work in minimal source code. total += nested_sum(i) else: total += i. The cumulative sum is not taken in place, you have to assign the return value: cum_l = np. Still a,b tuples and a_list_of_tuples are different (the diffence might be exposed in what solution is the most efficient). # Mathematical Median of Cumulative Records. I swapped the order of the sub-questions to make this more useful for the most common case that most beginners are searching for. Aug 24, 2017 · And to explain it, in mylist (list of lists) I want to check each list for the index 0 (first element) when it founds the same value element (in my example 16 ===16) and do the fallowing operation: keep only the first list and accumulate to it index 1 + index 2 (like this example -> 'August', 2014 and 'Iunie', 2014 to 'August 2014, Iunie 2014 Apr 9, 2021 · Python list is an ordered sequence of items. Type of the returned array and of the accumulator in which the elements are summed. Dec 27, 2023 · Python List Comprehension Syntax. Method # 1: Using Naive method. For example, the cumulative sum of [1, 2, 3] is [1, 3, 6]. 00:56 and start off with the open and close square brackets. 5,326 3 27 39. Jan 27, 2018 · I have a double sum which reads basically. Its primary strength lies in its simplicity and Python’s built-in efficiency. Python 2. If you would rather watch some video instruction, the following video will cover most of the same material. They can help make your programs easier to read and easier to maintain . Below is the demonstration of the same −Example Dec 30, 2016 · Given the following list: a=[1,2,3] I'd like to generate a new list where each number is the sum of it and the values before it, like this: result = [1,3,6] Logic: 1 has no preceding value, so it stays the same. I hope can help you. Here is my code so far: May 6, 2020 · A list comprehension is an elegant, concise way to define and create a list in Python. In Python3, To find the cumulative sum of a list where the ith element is the sum of the first i+1 elements from the original list, you may do: a = [4 , 6 , 12] b = [] for i in range(0,len(a)): b. answered Jul 4, 2018 at 17:25. This is what I have tried so far, but it does not output the same thing: res = [sum((A[i][j] * X[i]) for i in range(n) for j in range(n))] Note that Python's official style-guide, PEP8, recommends using lower_case names for variables, so I changed all your Ls to l and all your new_L to new_l. This approach shows all the shortcomings of using recusion in Python Sep 26, 2022 · I want to get my code to loop so that every time it performs the calculation, it adds basically does a cumulative sum for my variable delta_omega. # Example usage: Nov 19, 2012 · And call the same method with the rest of the list. Number of subset is input. Mar 10, 2024 · Method 2: Using Python’s accumulate() Function. We can do this as follows: new_list = [num for num in num_list if num > 10] new_list. But, other than the function itself, this solution has the same advantages of a one-line list comprehension in that it, well, takes up one line :-) Aug 24, 2016 · Here is a script to test the speed of each of the approaches ITT, as well as a chart with timing results: from collections import deque from copy import deepcopy Nov 26, 2013 · Here is a concept to abuse the original intent of the := "walrus operator" introduced in Python 3. Now just combine the two: {key:cumSum(*lists) for key,lists in groupby_station(inputList)} Note that my definition of cumulative sum is slightly different from yours; you can modify the cumSum function to match your definition. This way you avoid having to test whether the new_l already has an element in it: Jun 29, 2021 · 1. Python’s reduce() is a function that implements a mathematical technique called folding or reduction. The first part is triggered as long as if x ( that is to say x is not empty ). As an additional and interesting use case, you can concatenate lists and tuples using sum(), which can Jan 22, 2024 · For small or even medium-sized lists, this is generally fine. I am familiar with the built-in sum () function for lists and have used it before, eg: when the list contains integers, but I'm in a situation where I have instances from a Class and I need them summed. Mar 10, 2024 · Method 3: Cumulative Index Method. Using list comprehension and list slicing, find the cumulative sum of elements in the list. loop and append the current element with the previous appended element. Use list comprehension to iterate over the tuples in test_list. The problem statement asks to produce a new list whose i^ {th} element will be equal to the sum of the (i + 1) elements. Putting it outside will avoid defining a new function at every iteration and your code will still produce the expected result. Jun 6, 2023 · I am a beginner in python programming. Finally, when the length of your original list becomes 0. Reveal Hint Use a list comprehension to compute the sum 13 +23 + ⋯ +103. The following is an example of this method: Dec 15, 2020 · If you really want to use list comprehension, you can make a new list with an equal number of list entries as your input data. Feb 26, 2024 · Sum All The Items In Python List Using For Loop. Python – List comprehension with two lists; Python – List comprehension containing If condition Apr 17, 2015 · I am learning how to code at the moment and am wondering how to get a running total. def sum_list(list_numbers): index = 0. Jun 27, 2021 · python multiply all elements in list; cumulative frequency for python dataframe; two sum in python with 0ms runtime; how to add all values in a list python without using sum function; python groupby sum single columns; sum all elements in a list python; pandas cumulative mean; Write a function called square_odd that has one parameter. The challenge is to get the sum of all elements of a list using lambda. Input array. However, you can try to parallelize your algorithm by starting at different positions in the list, search for the first non-zero entry right-adjecent to a zero and proceed from there. Initialize a sum variable sm=0. We shall go through all of them in our following tutorials. Aug 10, 2015 · I want to create new list according cumulative sums of numbers in a list. Happy comprehending! Aug 28, 2023 · Time Complexity: O(N), Here N is the number of elements in the list. For each tuple i, use the sum() function to add up all the elements in the Mar 19, 2024 · Python's list comprehensions can effectively replace map, filter, and reduce functions, enhancing code readability and efficiency. Example 5: Using add() function of operator module 00:33 We could probably use some slightly different functions and methods to make that work. List comprehensions are one of the easiest and most efficient ways to create lists in Python. run_salary = 0. Mar 7, 2018 · This structure is similar to what the itertools. 5 / 2. Aug 3, 2011 · 2. In this, we perform the task of getting all the frequencies of all rows, and then check in the list occurrence of the required element from the row, sum () is used to get a summation of extracted frequencies in rows. Python. Nested Lists and List Comprehension are also discussed in detail with examples. Python to the old school style!. oblist) answered Aug 18, 2010 at 3:37. Using list comprehension, we'd like to append any values greater than ten to a new list. 8. The first way to find the sum of elements in a list is to iterate through the list and add each element using a for loop. How to calculate sum using list comprehension. append(run_salary) total_employees += increment. May 2, 2023 · Method 5: Using a list comprehension. Print the original list and the new list. Exit. Syntax: newList = [ expression (element) for element in oldList if condition ] Parameter: expression: Represents the operation you want to execute on every item within the iterable. Here’s an example: original_list = [1, 2, 3, 4] cumulative_sum = [sum(original_list[:i+1]) for Dec 29, 2022 · Pandas Series. Start iterating over the input list, with Jun 24, 2016 · and sum can take a generator, as sum( (x for x in range(10)) ), and as PEP289 said if a function call has a single positional argument, it can be a generator expression without extra parentheses, but in all other cases you have to parenthesize it. You can use Python’s built-in sum() function along with a list comprehension to sum all the numbers in a nested list. Auxiliary Space: O (n), the space required to store the result list. numpy. Quantity of integers is number of subsets 1. Append the split strings to a new list and store it in res variable. Sample Solution: Python Code: # Define a function named nums_cumulative_sum that takes a list of numbers (nums_list) as an argument. The real example of a cumulative sum is the increasing amount of water in a swing pool. Method #2: Using numpy array. Syntax: Series. There’s just one step to solve this. By multiplying the value at index i by the number of times it will appear in the sublists, we can obtain the sum in O (n) time. In this tutorial of Python Examples, we got introduced to List Comprehension in Python. freq = freq. Method 3: accumulate Function. Feb 24, 2024 · This article explores five efficient ways to achieve this common task in Python. I know this code is not correct because when the things got re-initialized the process should start all the way from 1st employees again and not the next employee in the list. Here’s an example: from itertools import accumulate. In Python 2. List comprehensions are actually one of my favorite features in Python. Let’s compare the two approaches: List Comprehensions: List comprehensions provide a concise way to create lists by applying an expression to each element of an Jul 4, 2018 · 2. from_iterable() and sum(). 2) How to Sum a Nested List Using sum() Function With List Comprehension. def nested_sum(L): total = 0 # don't use `sum` as a variable name. Return the cumulative sum of the elements along a given axis. 3 is from the first value (1) added to the value of the second number in the list (2) 6 is from the sum of 1 and 2 from the first two Nov 27, 2020 · 1. It is a built-in function, but requires importing itertools. low = low. sum = exp( x^2 + y^2 ) Of course, I could simply use two nested for loops but that tends to be time consuming for large numbers. 1 3 + 2 3 + ⋯ + 10 3. You had just used i incorrectly in the outer loop statement. Axis along which the cumulative sum is computed. In this method we use for loop which iterates through each element in the list, adding it to a running total. Feb 9, 2017 · def running_average(): sum = 0 count = 0 while True: sum += cauchy(3,1) count += 1 yield sum/count Or, given a generator for Cauchy numbers and a utility function for a running sum generator, you can have a neat generator expression: 2. Program of Cumulative sum in python What is the cumulative sum? The cumulative sum means "how much so far". It then constructs a new dictionary using dictionary comprehension. self. Share. for every calculation, it takes the previous values in the delta_omega array, adds them together and uses that value to perform the calculation again and so on. sum( [x**2 for x in range(10)] ) but in this case the Aug 9, 2020 · I came across this problem when in an interview. values=[1,2,3] for i in range(len(values)): print(sum(values[0:i])) Output is. Each subset of output represents increment integers [0,1,2,3,], which replace original input. In this article, we will discuss different ways to find the sum of elements in a list in python. Also, learn how to iterate the list and access the elements in the list in detail. There are many other scenarios where List Comprehension is used, and how it is used. e. It initializes an list containing numbers from 1 to 7. I am trying to perform cumulative addition on values of a list. Cumulative sum of a list [a, b, c] is defined as [a, a + b, a + b + c, ). This article will give you an overview of how list comprehension works and show you several examples. This problem can be solved using the combination of above two functions in which we use list comprehension to extend the logic to each element, sum function to get the sum along, slicing is used to get sum till the particular index. – Dec 13, 2023 · Python program to find Cumulative sum of a list The problem statement asks to produce a new list whose i^{th} element will be equal to the sum of the (i + 1) elements. You can just collapse the for loop into another level of comprehension: total = sum(sum(v. Method 1: Using the Built-in sum() Function. median () This is the most generic method to perform this task. It can be less efficient than other methods, as sum is called repeatedly for each element. Input is ideal - can be splitting to subset, sum of each subset is equal. The definition of the cumulative sum is the sum of a given sequence that is increasing or getting bigger with more additions. In this article you will learn the different methods of creating a list, adding, modifying, and deleting elements in the list. You could do it like this: euclst = [primelst[0]] for p in primelst[1:]: euclst. For example, your function might be used with a function like this: def add2(x, y): return (x + y,) * 2 # Returning the same thing twice, new sum and accumulate sum the same Apr 17, 2023 · Median of Records is : 4. And add the sum to your temp list as new element. My answer is. It uses list comprehension to find the cumulative sum. You should not use a list comprehension in this case. Python List Comprehensions consist of square brackets containing an expression, which is executed for each element in an iterable. I have this Class: def __init__(self, low, high, freq): self. 4. if count <= total_employees: run_salary += items[1] else: emp_bucket. Method #2 : Using chain () + statistics. I know they can seem a little bit arcane at first or a little bit strange, but they are actually super helpful. You seem to want the sum of all values to the end of the list after each element. This method is compact and can be written in a single line. 5, you could use helper function to raise StopIteration inside list comprehensions, that was however changed with PEP 479. It’s one of the simple approaches that returns the sum of all items sequentially within the list. For this, we will first Aug 18, 2023 · We are using dictionary comprehension in Python. In this we directly use inbuilt function after flattening using chain () to perform the median of the flattened list. list2 = [list_numbers[index]] while index < (len(list_numbers) - 1): item = list_numbers[index] + list_numbers[index + 1] Apr 26, 2023 · Auxiliary space: O(n) where n is the number of elements in the list “test_list”. Time complexity: O (n^2), where n is the length of the outer list. 3025 3025. In Python, you have two options for applying a function to each element of an iterable: using list comprehensions or the map function. Follow Python how to sum duplicates in list?-2. Method #1 : Using Counter () + list comprehension. iterable: specify the sequence of elements you want I want to write a function that takes a list of numbers and returns the cumulative sum; that is, a new list where the ith element is the sum of the first i+1 elements from the original list. If you wanted the sum of these numbers, you could of course say. Though the answers work almost verbatim in both cases. Reveal Hint Use a list comprehension or NumPy array to define a function in Python that returns the list of Mar 22, 2023 · As an additional list of the same length as the input list is created to store the prefix sum values. (since current result depends on previous results, it's not easily doable in a list comprehension) A list comprehension should be used. def nums_cumulative_sum(nums_list): # Use a list comprehension to calculate the cumulative sum for each element in the input list. It assigns variables as part of a larger expression. def cum_sum(nums): return [sum(nums[0:i+1]) for i in range(len(nums))] This is very ugly, the previous result has not been used later which results in redundant calculations. squares = [number** 2 for number in numbers] Code language: Python (python) A list comprehension consists of the following parts: An input list ( numbers) A variable that represents the elements of the list ( number) An output expression ( number**2) that returns the elements of the output list from the elements of the input list. By Shivang Yadav Last updated : September 18, 2023 . 6+ because of the f-string syntax in the list comprehension. Your statement to compute a commulative sum within the loop is correct. Filter. Tricks (and Hacks) In the previous sections, we've seen some obscure features of list comprehensions that might or might not be very useful in day-to-day coding. Find Sum Of Elements In A List Using For Loop. Adding several numbers together is a common intermediate step in many computations, so sum() is a pretty handy tool for a Python programmer. Method #2 : Using zip() + accumulate() + sum() + list slicing Apart from using the list comprehension to perform the task of binding, this method uses zip function to hold sublist element together, accumulate function joins the elements, and slicing is used to construct the required slicing. : b = [[5, 6], [7, 8]] Jan 6, 2013 · This question about a list of tuples. My impression of the intent was to save the user from calculating something in the test portion of an if and then have to calculate it again in the executable portion. All you need to do is slice your original data and generate sums for each slice. Here, I am creating a set of keys from all the three dicts. To find the cumulative sum of numbers in a list in Python, # Calculate the cumulative sum using a list comprehension cumulative_sum = [sum(input_list[:i+1]) for i Feb 17, 2013 · You need to use isinstance to check whether an element is a list or not. element: The term “variable” refers to each value taken from the iterable. Auxiliary Space: O(1), As constant extra space is used. Pythonic and efficient, especially for iterator-based processing. List Comprehensions. You have to do this for positive and negative values separately, though: Python’s built-in function sum() is an efficient and Pythonic way to sum a list of numeric values. So I want to try that out. Calculate the cumulative sum Feb 13, 2012 · Python 2. >>> sum_func(range(100)) 4950. Write a program to input a list of number and. Here's how you can do it using both approaches: Oct 19, 2013 · Here's an alternative using dictionary comprehension with itertools. 7 (r27:82525, Jul 4 2010, 09:01:59) [MSC v. We've got a list of numbers called num_list, as follows: num_list = [4, 11, 2, 19, 7, 6, 25, 12] Learn Data Science with. using the function sum() with a list comprehension in python. mylist = [10, 20, 30, 40, 50] total_sum = 0. for i in L: if isinstance(i, list): # checks if `i` is a list. Oct 13, 2021 · Python List Comprehension with Sum. count = 0. The requirement is to realize cumulative sum in one line of python. This method leverages the contribution of each element to the final sum, which depends on its position within the array. for i in range(n): for j in range(n): Y[i] += A[i][j] * X[j] return Y. For example, first element should be the same (31), second = 28+31, third = 31+28+31 and so on. startswith("A")] Map. I can use one list comprehension to replace the inner for loop, see here: Dec 18, 2017 · How would I write the following using list comprehension? Y = [0]*n. Aug 18, 2010 · 8. g. The lambda takes in two input parameters and returns the sum of the two elements. Example: Feb 15, 2018 · There can't be a sequential solution that is better than linear in the length of the list. append(euclst[-1]*p) initialize your list with first element. May 8, 2023 · Method 1: Using list comprehension + sum () + list slicing. high = high. anotherob) for ob in self. #. cumsum(axis=None, skipna=True) Parameters: axis: 0 or 'index' for row wise operation and 1 or 'columns' for column wise operation skipna: Skip This is a terrible idea. Python’s list comprehension combined with the sum() function can be used to produce the cumulative sum in a more Pythonic way. 7. For each odd number var in the list, it calculates the cube of the number and assigns the result as the value to the key var in the dictionary. Jan 9, 2022 · We often need to perform different operations on lists. 1500 32 bit (Intel)] on win32 = operator), we can use and increment a variable within a list comprehension Feb 1, 2016 · Among the ways to obtain the sum of a list A of ints in Python are the following two: Built-in sum function: sum (A) Reduce function with adder lambda: reduce (lambda x, y: x + y, A) Is there any speed advantage to using either of these, or are their performances roughly the same? On my machine the "sum" function appears to be way faster than Jul 15, 2018 · I have a list that contain days count in each month: month = [31,28,31,30,31,30,31,31,30,31,30,31] I want to transform list above. cumsum() is used to find Cumulative sum of a series. 1. If you want to sum the squares of the first one-thousand integers, then a list comprehension will solve this problem admirably: Python. We show examples for filtering, mapping, and reducing list items, demonstrating the simplicity and power in Python programming. Examples : We will use the concept of list comprehension and list slicing to get the cumulative sum of the list. Apr 27, 2023 · Let’s see some of the methods to sum a list of list and return list. Using reduce () and split (), iterate through each split and concatenate them with spl_char using lambda function. To find the cumulative sum of numbers in a list in Python, you can use a loop or a list comprehension to iterate through the list and calculate the cumulative sum at each position. The input list is passed to the function cumSum () which returns the cumulative sum list. I have created this function that takes as parameter a list and return a new list with the previous element summed. I would suggest changing the input so each element is unique and its easier to follow, e. Mar 10, 2021 · Following is a program to form a cumulative sum list using the input list −. 0. names_starting_with_a = [name for name in all_names if name. chain. Oct 12, 2016 · Note: this code only works with Python 3. Print the original list of tuples. Each element of the new list is equal to the sum of all elements in a particular position. l = [4, 2, 1, 3] You should keep track of the cumulative sum in a variable. 0 1 3 Whereas I am expecting a list with output [1,3,6] Please can you someone guide me which part of my code is wrong? I don't wish to use accumulate() function. cumsum. May 16, 2023 · Step-by-step approach: Initialize the list test_list and print it. 6 You could use vars()['_[1]'] to refer to the list 4. 5. 6 Hack. Examples : Input : list = [10, 20, 30, 40, 50]Output : [10, 30, 60, 100, 150]Input : list = [4, 10, 15, 18, 20]Output : [4, 14, 29, 47, 67] Approach 1 : We will use the concept Apr 23, 2017 · One approach would be just to successivly pop and add the first element until the sequence is exhausted: >>> sum_func = lambda x: x[0] + sum_func(x[1:]) if x else 0. cumsum(l) print(cum_l) You don't need to place that function in the for loop. Cumulative sum of a list [a, b, c, ] is defined as [a, a+b, a+b+c, ]. (5 + 5 = 10 - 5 = 5 * 5 = 25 / 5) = 5. 2. vk cq hq oy lz rz uk mm kk qo