Lists, Looping the Lists, Functions

$1.$ Open Visual Studio Code then open this week's HOS assignment that you just cloned

from GitHub.

$1.$ Open the repository that you just cloned from GitHub.

Lists

The list is a most versatile datatype available in Python which can be written as a list of commaseparated values $($items$)$ between square brackets. The important thing about a list is that items

in a list need not be of the same type.

Creating a list is as simple as putting different comma$-$separated values between square brackets.

For example $$

list$1=[\text{'}$physics$\text{'},$ 'chemistry', $1997,2000]$;

list$2=[1,2,3,4,5]$;

list$3=["$a$","$b$","$c$","$d$"]$

Python considers the first item in a list to be at position $0,$ not position $1.$

$1.$ Under Module$1$ create a file called List$\_$basic.py and type the following code

Accessing values

To access values in lists, use the square brackets for slicing along with the index or indices to

obtain value available at that index.

$1.$ In the same file List$\_$basic.py add the below code

$2.$ Type the following in the terminalto check the output of the above code

$>>>$ python$3$ List$\_$basic.py

Updating Lists

$1.$ In the same file List$\_$basic.py add the below code

$2.$ Type the following in the terminalto check the output of the above code

$>>>$ python$3$ List$\_$basic.py

Adding element to a list$-$ Appending

The simplest way to add a new element to a list is to appendthe item to the list. When you

append an item to a list, the new element is added to the end of the list. The append$()$method

makes it easy to build lists dynamically.

$1.$ In the same file List$\_$basic.py add the below code

$2.$ Type the following in the terminalto check the output of the above code

$>>>$ python$3$ List$\_$basic.py

Adding element to a list$-$ Inserting elements

You can add a new element at any position in your list by using the insert$()$method$.$ You do this

by specifying the index of the new element and the value of the new item.

$1.$ In the same file List$\_$basic.py add the below code

$2.$ Type the following in the terminalto check the output of the above code

$>>>$ python$3$ List$\_$basic.py

Removing element

There are $3$ ways to remove an element from a list.

i$)$ If you know the position of the item you want to remove from a list, you can use

the del statement.

ii$)$ The pop$()$ method removes the last item in a list, but it lets you work with that item after

removing it$.$ The term pop comes from thinking of a list as a stack of items and popping

one item off the top of the stack. In this analogy, the top of a stack corresponds to the end

of a list. You can use pop$()$ to remove an item from any position in a list by including the

index of the item you want to remove in parentheses.

iii$)$ If you only know the value of the item you want to remove, you can use

the remove$()$ method.

$1.$ Under Module$1$ create a file List$\_$remove.py and type the following code.

$2.$ Type the following in the terminalto check the output of the above code

$>>>$ python$3$List$\_$remove.py

The del used at index $1$ deletes the value Yamaha. You can no longer access the value

that was removed from the list after thedelstatement is used.

$3.$ Add the below code in the same file

$4.$ Type the following in the terminalto check the output of the above code

$>>>$python$3$List$\_$remove.py

Atpop$(),$ a value from the list and store that value in the variablepopped$\_$motorcycle. We print

the listto show that a value has been removed from the list. Then we print the popped value to

prove that we still have access to the value that was removed.

The output shows that the value $$suzuki$$was removed from the end of the list and is now

assigned to the variablepopped$\_$motorcycle.

$5.$ Add the below code in the same file

$6.$ Type the following in the terminalto check the output of the above code

$>>>$python$3$List$\_$remove.py

The code removes $$ducati$$ from the list. You can use the remove$()$ method to work with a value

that is being removed from a list.

Using Loop in lists

$1.$ Create a file replaceNegative.py and enter the following code. The program replaces any

negative numbers in the list with positive ones.

$2.$ Type the following in the terminalto check the output of the above code.write the answer each step clearly including images