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● mean(): The mean()method yields the mean of the elements of a list. As the function mean() is available in the
statistics module, we need to import the statistics module first. For example,
>>> import statistics
>>> lst = [ 4, 12, 7, 9]
>>> statistics.mean(lst)
8
We summarise the discussion of the above methods in Table 7.1.
Table 7.1: Commonly Used Built-in Functions on Lists
S. No. Function Description Examples
1. max(list) It returns the largest element >>> lst=[3, -2, 0, 78, 25]
from a list. >>> max(lst)
78
2. min(list) It returns the smallest element >>> lst=[3, -2, 0, 78, 25]
from a list. >>> min(lst)
-2
3. sum(lst [,num]) It returns the sum of all numeric >>> lst =[1, 3, 5, 7]
values in the given list. The >>> sum(lst)
optional argument num, when 16
provided, is added to the sum of >>> sum(lst,5)
the elements of the list.
21
4. from statistics It returns the mean of the >>> lst = [1, 2, 3, 4, 5]
import mean elements of a list. >>> from statistics import mean
mean(lst) >>> mean(lst)
>>> 3
7. 7 List Methods
Python provides several methods to manipulate lists. Below, we will discuss some of these methods with an example
list: lst. These methods do not create a new list; they modify the original list: lst. Such an operation that takes
place on an existing object is said to be in place.
● lst.append(elem): The method append() inserts the object elem, passed as an argument, at the end of
the list lst.
Example:
>>> lst1 = [10, 20, 30, 40]
>>> lst1.append(35)
>>> lst1
[10, 20, 30, 40, 35]
● lst.insert(index, elem): The method insert() inserts the object elem, passed as an argument, at
the specified index.
For example,
>>> names = ['Aryan', 'Anthony', 'Sunpreet', 'Venkatesh']
>>> names.insert(2, 'Samantha')
>>> names
['Aryan', 'Anthony', 'Samantha', 'Sunpreet', 'Venkatesh']
178 Touchpad Informatics Practices-XI

