How To Find The Average Of A List In Python

There are ii ways to find the average of a list of numbers in Python. Yous can divide the sum() past the len() of a list of numbers to find the average. Or, you can notice the average of a list using the Python hateful() function.

Finding the average of a ready of values is a common job in Python.

For example, you lot may take a list of product sales and want to find out the average purchase cost. Or, for a variety report, yous may want to calculate the average age of employees who work for your organization.

Python Average

At that place are two methods employed to observe the average of a list of numbers in Python:

By calculating the sum of the list and then dividing that number past the length of the listing. The length of the list is how many values are in the list. or;
By using the statistics.mean() method.

While both methods return the average of a list of numbers, at that place are different factors you should consider when choosing which one to apply.

In this tutorial, we discuss how to use the aforementioned approaches to detect the average of a list in Python. We'll walk through 2 examples to help you get started.

Python Average: Len() and Sum()

The formula for calculating the average of a list of values is the sum of all terms divided by the number of those terms. We tin utilise the Python sum() and len() values to calculate the average of the numbers in a list.

The Python len() method calculates and returns a count of numbers in a list. len is short for length, referring to the length of—or number of—items in a list.

81% of participants stated they felt more confident about their tech job prospects subsequently attention a bootcamp. Get matched to a bootcamp today.

The average bootcamp grad spent less than six months in career transition, from starting a bootcamp to finding their showtime chore.

The sum() method in Python calculates the total sum of all values in a list.

We tin use these functions together to calculate the boilerplate value from a list of values.

The basic formula for calculating an boilerplate in Python is:

avg_value = sum(list_of_values) / len(list_of_values)

This arroyo is common because you practice not have to import any external values to calculate an average.

sum() and len() Function Example

Let's say that nosotros run a coffee store and want to know the average toll of all orders placed then far today. To calculate this number, we could employ the sum() and len() methods that nosotros only discussed:

orders = [2.l, 4.l, 2.00, 2.75, ii.50, 5.00, 8.00, 2.25]  average = sum(orders) / len(orders)  print("The average coffee society price today is $" + str(circular(average, 2)))

We print the average value to the panel:

The average coffee order toll today is $3.69

On the first line of our code, we define a Python variable. This variable stores a list of order prices. And then, we calculate the average of those orders by dividing the sum of all orders by the length of our guild list.

form-submission

Find Your Bootcamp Friction match

Career Karma matches you with top tech bootcamps
Go exclusive scholarships and prep courses

At the end of our code, we print out a message to the panel that tells the states the average cost of coffee orders.

We use the Python round() method to round our average to two decimal places. The str() method to converts our average value into a cord that nosotros tin can print to the console.

At present we know the average coffee order price then far today is $iii.69.

Python Boilerplate: statistics.mean()

The Python statistics library contains a role called statistics.mean() that calculates the hateful value of a list of values. The term mean is used in mathematics to describe the average of a list of values.

The syntax for the statistics.mean() method is:

statistics.mean(list_of_values)

The mean() method takes in one parameter: the list of items whose average you want to calculate.

Before we utilise this method, we need to import the statistics module (statistics) in Python. This is a born module that can exist used to perform diverse calculations in Python.

This is an important difference between using statistics.mean() and the sum() and len() method. The sum() and len() method can exist used without importing whatsoever libraries. Simply, you need to import statistics to apply statistics.hateful().

If y'all exercise not heed importing another library, this method works fine. Considering you lot can calculate an average value without whatever libraries, you should consider doing and then earlier using the statistics library.

We tin import the statistics module using a Python import argument:

Venus profile photo

"Career Karma entered my life when I needed it near and speedily helped me friction match with a bootcamp. Two months later on graduating, I found my dream task that aligned with my values and goals in life!"

Venus, Software Engineer at Rockbot

We can now access the mean() function in the statistics library.

statistics.mean() Example

Now we're set to start calculating averages using mean().

Allow'south take the example of java orders that nosotros used to a higher place. Say we want to calculate the average price of the java orders placed so far today. Nosotros could use the following code to calculate the average price:

import statistics  orders = [2.50, 4.50, 2.00, two.75, 2.fifty, 5.00, 8.00, ii.25]  average = statistics.mean(orders)  impress("The average coffee club price today is $" + str(round(average, 2)))

Let's look at the result of our program:

The average java order cost today is $3.69

Our program returns the same text and outcome information technology did in our get-go example.

Calculate Average of a Tuple

We can apply the statistics.hateful() method to calculate the mean value of a tuple, which is an unchangeable, ordered sequence of items. Here'south an example of statistics.mean() being used to summate the average coffee social club price, with our information stored in a tuple:

import statistics  orders = (ii.50, four.50, two.00, 2.75, 2.50, 5.00, 8.00, 2.25)  average = statistics.mean(orders)  impress("The average java order price today is $" + str(round(average, two)), ".")

Our code returns the aforementioned response equally our last example considering we're working with the aforementioned numbers:

The boilerplate coffee gild cost today is $3.69.

A tuple may be used instead of a list if you are working with values that should not alter. Then, because our coffee gild prices volition not change after an club has been candy, a tuple is appropriate.

Mean of Negative Values

You tin use mean() to calculate the mean value of a fix of negative numbers.

Allow'due south say that nosotros take a list that stores the lowest daily temperatures recorded during a specific calendar week in winter. We could use the following code to summate the average of that week's everyman daily temperatures:

import statistics  temperatures = [-12, -14, -2, -5, -8, -four, -9]  average = statistics.mean(temperatures)  print("The average of this week's lowest daily temperatures is", circular(average, two), "degrees Celsius.")

Our code returns:

The average of this calendar week'due south lowest daily temperatures is -7.71 degrees Celsius.

Conclusion

Y'all can calculate the boilerplate of a list of values using the sum() and len() methods or the statistics.mean() method. The statistics.mean() method needs to be imported into your programme. Yous can use the sum() and len() method without importing any external libraries into your code.

Do you desire to learn more about how to code in Python? Read our How to Learn Python guide. This guide contains a list of top learning resources you can use to advance your cognition.