Hi Folks! In this article, we will have a look at the various **ways to find the average of a list in a Python List**.

In general, an average is a value that represents a whole set of data items or elements.

Formula: Average = summation of numbers/total count.

## Techniques to find the average of a list in Python

Either of the following techniques can be used to calculate the average/mean of a list in Python:

**Python mean() function****In-built sum() method****Python lambda and reduce() method****Python operator.add() method**

### 1. Python mean() function

**Python 3** has `statistics module`

which contains an in-built function to calculate the mean or average of numbers. The `statistics.mean() function`

is used to calculate the **mean/average of input values or data set**.

The **mean() function** accepts the list, tuple or data-set containing numeric values as a parameter and returns the average of the data-items.

**Syntax:**

mean(data-set/input-values)

**Example:**

from statistics import mean inp_lst = [12, 45, 78, 36, 45, 237.11, -1, 88] list_avg = mean(inp_lst) print("Average value of the list:\n") print(list_avg) print("Average value of the list with precision upto 3 decimal value:\n") print(round(list_avg,3))

In the above snippet of code, we have used `statistics.round()`

method to **round off the output average up to a particular decimal value**.

**Syntax:**

statistics.round(value, precision value)

**Output:**

Average value of the list: 67.51375 Average value of the list with precision upto 3 decimal value: 67.514

### 2. Using Python sum() function

Python `statistics.sum()`

function can also be used to find the average of data values in Python list.

The `statistics.len()`

function is used to calculate the length of the list i.e. the count of data items present in the list.

**Syntax:**

len(input-list)

Further, `statistics.sum()`

function is used to calculate the sum of all the data items in the list.

**Syntax:**

sum(input-list)

Note: **average = (sum)/(count)**.

**Example:**

from statistics import mean inp_lst = [12, 45, 78, 36, 45, 237.11, -1, 88] sum_lst = sum(inp_lst) lst_avg = sum_lst/len(inp_lst) print("Average value of the list:\n") print(lst_avg) print("Average value of the list with precision upto 3 decimal value:\n") print(round(lst_avg,3))

**Output:**

Average value of the list: 67.51375 Average value of the list with precision upto 3 decimal value: 67.514

### 3. Using Python reduce() and lambda method

We can use **Python reduce()** function along with the **lambda()** function.

**Python reduce() function**: The `reduce() function`

is basically used to apply a particular(input) function to the set of elements passed to the function.

**Syntax:**

reduce(function,input-list/sequence)

- Initially, the reduce() function applies the passed function to the first two consecutive elements and returns the result.
- Further, we apply the same function to the result obtained in the previous step and the element succeeding the second element.
- This process continues until it reaches the end of the list.
- Finally, the result is returned to the terminal/screen as output.

**Python lambda() function:** The `lambda() function`

is used to build and form Anonymous functions i.e. function without a name or signature.

**Syntax:**

lambda arguments:function

**Example:**

from functools import reduce inp_lst = [12, 45, 78, 36, 45, 237.11, -1, 88] lst_len= len(inp_lst) lst_avg = reduce(lambda x, y: x + y, inp_lst) /lst_len print("Average value of the list:\n") print(lst_avg) print("Average value of the list with precision upto 3 decimal value:\n") print(round(lst_avg,3))

**Output:**

Average value of the list: 67.51375 Average value of the list with precision upto 3 decimal value: 67.514

### 4. Python operator.add() function to find the average of a list

**The Python operator module** contains various functions to perform basic calculations and operations efficiently.

The `operator.add()`

function can be used to calculate the summation of all the data values present in the list with the help of **Python reduce() function**.

**Syntax:**

operator.add(value1, value2)

**Note: average = (sum)/(length or count of elements)**

**Example:**

from functools import reduce import operator inp_lst = [12, 45, 78, 36, 45, 237.11, -1, 88] lst_len = len(inp_lst) lst_avg = reduce(operator.add, inp_lst) /lst_len print("Average value of the list:\n") print(lst_avg) print("Average value of the list with precision upto 3 decimal value:\n") print(round(lst_avg,3))

**Output:**

### 5. NumPy average() method to calculate the average of a list in Python

Python’s NumPy module has an in-built function to calculate the average/mean of the data items present in the data set or list.

The `numpy.average()`

method is used to calculate the average of the input list.

**Example:**

import numpy inp_lst = [12, 45, 78, 36, 45, 237.11, -1, 88] lst_avg = numpy.average(inp_lst) print("Average value of the list:\n") print(lst_avg) print("Average value of the list with precision upto 3 decimal value:\n") print(round(lst_avg,3))

**Output**:

## Conclusion

Thus, in this article, we have unveiled and understood various techniques to find the average of a Python List.

## References

- NumPy average() method – Official Documentation
- The operator module – Official Documentation
- Python NumPy module
- Python List