The 5 ways to find the average of a list in Python

What is the mean of a list?

Before diving into ways to find the mean of a list in Python, it's important to understand what the mean is. It is the central numerical value of a dataset obtained by summing all the values and dividing the result by the number of elements in the list.

The mean is an important concept in statistics and many practical applications in areas such as data science, engineering, and economics. By calculating the mean, we can gain a deeper understanding of how the data is distributed and how a population or sample behaves.

In Python, there are many different ways to find the mean of a list, from using built-in functions to creating your own custom functions. Once this is clarified, we will present 5 ways to find it.

Way 1: Using the sum() and len() function

The sum() function takes a list of numbers as an argument and returns the sum of all of them. On the other hand, the len() function returns the number of elements in a list. Using these two functions together, we can easily calculate the average of a list in Python.

Here is an example of the code:

list = [2, 4, 6, 8, 10].
average = sum(list) / len(list)
print("The average of the list is:", average)

In this example, we create a list of numbers and then use the sum() function to sum all the elements in the list. Next, we divide the result of the sum by the number of elements in the list using the len() function. Finally, print the result as the value of the average.

info With just two built-in Python functions, you can easily calculate the average of any list of numbers you have.

Way 2: Using the mean() function of NumPy

NumPy is a Python library used for numeric and scientific computation. One of its built-in functions is mean(), which is used to find the mean of a set of numbers.

To do this you would have to use, for example, this code:

import numpy as np

list = [2, 4, 6, 6, 8, 10]
mean = np.mean(list)
print("The mean of the list is:", mean)

This time, we import NumPy with the syntax import numpy as np. Then, we create a list of numbers and use NumPy's mean() function to calculate the average of the list. Finally, print the result as the value of the average.

info With the NumPy library, you can perform complex numerical calculations quickly and efficiently in Python.

Way 3: Using the statistics.mean() function of the statistics library

The statistics library is a Python library that includes several useful statistics functions. One of these functions is mean(), which is used to calculate the mean of a list of numbers.

Here is an example of the code:

import statistics

list = [2, 4, 6, 6, 8, 10]
average = statistics.mean(list)
print("The mean of the list is:", mean)

In this case, we import the statistics library with the import statistics syntax. Then, we create a list of numbers and use the mean() function of statistics to calculate the mean of the list. Finally, print the result to obtain the mean value.

info The statistics library is very useful to perform statistical and mathematical calculations in Python in a simple way.

Way 4: Using a for loop and summing the elements of the list

Another way to calculate the average of a list in Python is to use a for loop to sum all the elements in the list and then divide that sum by the amount of elements in the list.

An example of code you can try:

list = [2, 4, 6, 8, 10].
sum = 0
for num in list:
    sum += num
average = sum / len(list)
print("The average of the list is:", average)

Here we create a list of numbers and use a for loop to sum all the elements in the list. Then, we divide that sum by the number of items in the list to get the average. Finally, we print the result as the value of the mean.

info This way of calculating the mean is a bit more complex than the previous ones, but it is very useful when you don't have access to external libraries or just prefer to use simpler, more straightforward Python code.

Way 5: Using the reduce() function in the functools library

The reduce() function of the functools library allows us to apply an operation to all elements of a list in cumulative fashion. To calculate the average of a list using reduce(), we first need to import the functools library and the reduce() function. Then, we use reduce() to sum all the elements in the list and divide that sum by the number of elements in the list.

Here is a code example:

from functools import reduce

list = [2, 4, 6, 8, 10].
sum = reduce(lambda x, y: x + y, list)
average = sum / len(list)
print("The average of the list is:", average)

In this example, we import the functools library and the reduce() function. Then, we create a list of numbers and use reduce() to sum all the elements in the list. Finally, we divided that sum by the amount of elements in the list to get the average.

info This way of calculating the average is very useful when you are working with large amounts of data and need a quick and efficient solution.

Extra: Creating a custom function.

Just as you read it, at the end we present you not only 5 ways to find the average of a list in Phyton, but six. This option can be useful if you need to perform additional calculations or if you want to customize the output of your function.

If you have the need to calculate the average of a list on multiple occasions in your code, it can be useful to create a custom function to make it easier and faster. A function is a block of code that performs a specific task and can be called at any time.

Here is an example code:

def calculate_average(list):
    sum = 0
    for num in list:
        sum += num
    average = sum / len(list)
    return average

list = [2, 4, 6, 8, 10].
average = calculate_average(list)
print("The average of the list is:", average)

In this example, we create a custom function called calculate_average that takes a list as parameter. Inside the function, we create a variable called sum that starts at zero and use a for loop to iterate over each number in the list and sum them. Then, we divide the total sum by the length of the list to get the average and return it as the result.

To use this function, we simply pass our list as an argument and store the result in a variable called average.

success Done! You now know six different ways to find the average of a list in Python. You can now take advantage of them in your tasks and/or projects.

Conclusions

We hope you found this tutorial helpful. Calculating the mean of a list is a common task in Python data analysis and programming, and these five options will allow you to do it quickly and efficiently. Also, remember that you can always customize your code and create your own function to suit your specific needs.

Don't be discouraged if you are not yet comfortable with Python. Programming can be challenging, but it can also be exciting and quite rewarding. With practice and perseverance, you will be able to master any Python task that comes your way.