# Series Summation in Python

This tutorial will discuss the methods to carry out series summation in Python.

## Series Summation Using the `for`

Loop in Python

Suppose we want to carry out a series summation like `1+2+3+...+n`

. We can use the traditional `for`

loop in Python to tackle this problem.

For this specific problem, we must set the range of the `for`

loop to `n+1`

with the `range()`

function and sum up each value inside the loop.

The `range()`

function takes the 3 parameters: starting position, ending position, and the step. If we don’t specify the starting position, the `range()`

function starts from 0 by default.

If we don’t specify the step parameter, the `range()`

function increments the values by 1. To execute correctly, we only need to set the ending position for the `range()`

function.

The following code snippet demonstrates a working implementation of this solution with the `for`

loop in Python.

```
sum = 0
n = 5
for x in range(1, n+1):
sum = sum + x
print(sum)
```

Output:

```
15
```

We initialized a `sum`

variable that would store our result. The variable `n`

is the value we want to execute summation.

Here, the variable `x`

increments from 1 to n in the loop. We keep adding this `x`

into our `sum`

variable until the loop ends and print the result after the loop ends.

## Series Summation Using the `sum()`

Function in Python

The `sum()`

function sums a list of values in Python. We can use this `sum()`

function with a list comprehension to get the desired list of values for summation.

We again have to specify `n+1`

as the upper limit of the `range()`

function.

The following example shows us how to carry out series summation with Python’s `sum()`

function.

```
sum = 0
n = 5
sum = sum(i for i in range(1, n+1))
print(sum)
```

Output:

```
15
```

Similar to the previous example, we initialized the `sum`

and `n`

variables to store the results and specify the summation range. The list comprehension used inside the `sum()`

function returns values from 1 to n, summed up and stored inside the `sum`

variable.

**Muhammad Maisam Abbas**

Maisam is a highly skilled and motivated Data Scientist. He has over 4 years of experience with Python programming language. He loves solving complex problems and sharing his results on the internet.

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