List With in the List in Python

In this class, we discuss list with in the list in python.

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List with in the List

To understand the concept of a list with in the list, Reader should have a basic understanding of list data type. Click here.

As we discussed list previously, a list is a collection of compound data types.

Placing a list in the list is possible because the list is a collection of compound data types.

Let’s take examples, and understand how to define a list and access-list within the list.

a=[“C”[“java”,”is”,”a”,”programming”,”language”],”python”,”is”,”programming”,”language”]

In the above example, the first element is of type string.

The second element is of type list.

When we display the above list.

print(a) will show [“C”,[“java”,”is”,”a”,”programming”,”language”],”python”,”is”,”programming”,”language”]

Display first index position element.

Print(a[1]) will display [“java”,”is”,”a”,”programming”,”language”].

The entire list is written in Index position one and considered as an element.

Access elements list within the list

Example:

a=[“C”,[“java”,”is”,”a”,”programming”,”language”],”python”,”is”,”programming”,”language”]

print(a[1][0]) will display java.

In the above print statement, we defined a[1][0]. It means in the first index position. We have a list.

In that list, the zero index position element should be displayed.

Similarly, we can define any number of levels we needed. List within the list within the list.

Example:

a=[“C”,[“java”,”is”,”a”,”programming”,”language”,[“C++”,”is”,”a”,”programming”,”language”]],”python”,”is”,”programming”,”language”]

In the above example, we have three levels of nested lists.

To access the elements present in the nested list. We use square brackets, as shown above.

print(a[1][5][3]) will display programming.

How to take the list from the user input?

a=[]
 n=int(input("enter the number of elements in the list"))
 for i in range(0,n):
     print("enter the element {}".format(i+1))
     element=int(input())
     a.append(element)
 print(" the entered list is",a)

The above program shows how to take elements from the user input and create a list.

In this program, we made an empty list.

We are taking the number of elements.

For loop executes for n times.

Each time take an element from the user and append it to the list.

How to take the list within the list from the user input?

a=[]
 n=int(input("enter the number of elements in the list"))
 for i in range(0,n):
     print("enter your name and id")
     element=[input(),int(input())]
     a.append(element)
 print(" the entered list is",a)

From the above program, we are taking the user name and identification number.

Each time it loops. We are taking details and placing them on a list.

The details list is appended to another list.

This is one of the ways we create a list with in the list from the user input.

How is memory assigned to the list? We discuss this in our next class