# 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.

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.