Python itertools.accumulate Function

The itertools.accumulate function in Python's itertools module returns an iterator that yields accumulated sums, or accumulated results of other binary functions, specified via the func parameter. It is useful for performing cumulative operations on iterable data.

Table of Contents

1. Introduction
2. itertools.accumulate Function Syntax
3. Examples
   • Basic Usage
   • Using a Different Binary Function
   • Using accumulate with a Lambda Function
4. Real-World Use Case
5. Conclusion

Introduction

The itertools.accumulate function creates an iterator that returns accumulated sums or results of a specified binary function. By default, it performs cumulative summation, but you can pass a different binary function to customize the operation.

itertools.accumulate Function Syntax

Here is how you use the itertools.accumulate function:

import itertools

iterator = itertools.accumulate(iterable, func=operator.add, *, initial=None)

Parameters:

• iterable: The input iterable whose accumulated values are to be computed.
• func: Optional. A binary function (default is operator.add) to perform the accumulation.
• initial: Optional. A starting value to include in the accumulation.

Returns:

• An iterator that yields accumulated values.

Examples

Basic Usage

Create an iterator that yields accumulated sums of numbers in a list.

Example

import itertools

numbers = [1, 2, 3, 4, 5]
accumulated_sums = itertools.accumulate(numbers)
print(list(accumulated_sums))

Output:

[1, 3, 6, 10, 15]

Using a Different Binary Function

Use the operator.mul function to accumulate the product of elements.

Example

import itertools
import operator

numbers = [1, 2, 3, 4, 5]
accumulated_products = itertools.accumulate(numbers, func=operator.mul)
print(list(accumulated_products))

Output:

[1, 2, 6, 24, 120]

Using accumulate with a Lambda Function

Use a lambda function to accumulate the maximum value.

Example

import itertools

numbers = [1, 5, 2, 6, 3, 7]
accumulated_max = itertools.accumulate(numbers, func=lambda x, y: max(x, y))
print(list(accumulated_max))

Output:

[1, 5, 5, 6, 6, 7]

Real-World Use Case

Cumulative Sum of Sales

Calculate the cumulative sum of daily sales.

Example

import itertools

daily_sales = [100, 200, 150, 300, 250]
cumulative_sales = itertools.accumulate(daily_sales)
print(list(cumulative_sales))

Output:

[100, 300, 450, 750, 1000]

Conclusion

The itertools.accumulate function is used for generating accumulated results from an iterable. Whether you need to perform cumulative summation, multiplication, or any other binary operation, accumulate provides a flexible and efficient way to handle such tasks.