Trupti at 04:37, 7 September 2017

2017-09-07T04:37:21Z

Trupti: Created page with "Python/C2/Getting Started with Lists/English '''Title of script''': '''Getting Started with Lists''' '''Author: Aditya Palaparthy''' '''Keywords: Python, IPython,''' '''lis..."

2017-09-06T10:41:50Z

Created page with "Python/C2/Getting Started with Lists/English '''Title of script''': '''Getting Started with Lists''' '''Author: Aditya Palaparthy''' '''Keywords: Python, IPython,''' '''lis..."

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Python/C2/Getting Started with Lists/English

'''Title of script''': '''Getting Started with Lists'''

'''Author: Aditya Palaparthy'''

'''Keywords: Python, IPython,''' '''list, del, remove, append'''

{| style="border-spacing:0;"
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <center>'''Visual Cue'''</center>
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <center>'''Narration'''</center>

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

containing title, name of the production team along with the logo of MHRD
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Hello Friends. Welcome to the tutorial on "'''Getting started with lists'''".

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Objectives

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| At the end of this tutorial, you will be able to,

* Create '''lists '''
* Access '''list elements '''
* '''Append elements''' to '''lists'''
* '''Delete elements''' from '''lists '''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show slide

System Specifications
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| To record this tutorial, I am using

* '''Ubuntu Linux 14.04''' operating system
* '''Python 3.4.3'''
* '''IPython 5.1.0'''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| doneAnimate the slideShow Slide

Pre-requisites
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| To practise this tutorial, you should know how to

* run basic '''Python '''commands on the '''ipython console'''

If not, see the relevant '''Python '''tutorials on this website.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

List
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| What is a List?

* A List can store a sequence of elements.
* All elements need not be of the same data types

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[Terminal]</nowiki>

'''ipython3'''

| style="background-color:#ffffff;border:1pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0cm;padding-right:0.191cm;"| let us open the '''Terminal '''by pressing '''Ctrl+Alt+T '''keys simultaneously

Now, type '''ipython3''' and press '''Enter'''.

We are now in the '''ipython''' prompt.

Let us clear the terminal by pressing Ctrl + L for better view.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''mylist<nowiki> = ['spam', 'eggs', 100, 1.234] </nowiki>'''

Highlight spam and eggs
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Let us define a '''list''' with a variable name '''mylist'''

Type

'''mylist '''''equal to'' ''inside square brackets inside quotes''''' spam '''''comma''''' '''''inside quotes '''''eggs''' ''comma''' ''hundred '''''comma''''' one point two three four '''and''' '''press '''Enter'''.

In Python, strings are always placed inside single or double quotes.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| '''type(mylist)'''

Highlight the command
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Now enter''' type '''within brackets '''mylist '''and'' ''press '''Enter'''.

Here type is a function which will return the datatype of the variable.

'''mylist''' is a list datatype.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Highlight according to narration
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| As we can see, lists can contain elements of different data types

In mylist, spam and eggs are '''strings''', whereas '''hundred''' and''' one point two three four''' are '''integer''' and '''float''' respectively. ‘

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show slide

What is a variable?

* variable must either start with an alphabet or an underscore.

* They cannot start with numbers and cannot be the same as Python keywords.

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| In the code typed earlier, the name '''mylist''' is a variable.

In Python, a variable must either start with an alphabet or an underscore.

They cannot start with numbers and cannot be the same as Python keywords.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Examples of Keywords:

* for, if, else, elif, while, in, def, or, and
* A variable name cannot have spaces or punctuation characters or any arithmetic characters.

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| You will learn about keywords as we proceed.

Few examples of keywords are “for, if, else, elif, while, in, def, or, and”.

A variable name cannot have spaces or punctuation characters or any arithmetic characters.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| show slide

Valid and invalid variables

Valid variable names:

* x, y, xx, abc, a_b_c, a1, variable1, mylist, _x
* foreign, spiff, while_true, or_else, and_od_else_1

Invalid names:

* 1_x, 2_var, x-, x+, x;, x:
* x y, x+y x*y x&^ae
* for, in, elif

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| These are some of the valid and invalid variable names:

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Switch to the terminal

Highlight '''<nowiki>mylist = ['spam', 'eggs', 100, 1.234] </nowiki>'''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Getting back to our lists, the list could be created as

num ''underscore ''list is ''equal to inside square brackets '''''one''' ''comma '''''two''' and press''' Enter'''

or

'''x '''''equal to inside square brackets inside quotes ''a'' comma inside quotes '''''b''''' ''and press''' Enter'''

Any valid variable name could be used.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''<nowiki>myemptylist = []</nowiki>'''

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Let us now create an '''empty list '''with no Can we use 'elements' instead of items. This is more in line with terms used when referring to a listelements.

Type '''myemptylist '''''is equal to open and close square brackets ''and'' ''press '''Enter'''.

This is an '''empty list''' without any '''element'''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| slide

list index

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| We can access an element of a list using its corresponding index or position.

Index value of the elements starts from 0, 1, 2 and so on.

'''Negative indices''' are used to access '''elements''' from the end.

Which starts from -1, -2, and so on

The syntax to get a specific list element is

'''variable '''''inside square brackets element’s '''''index value'''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"|
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Switch to the terminal

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''<nowiki>mylist[0]</nowiki>'''

'''<nowiki>mylist[1]</nowiki>'''

'''<nowiki>mylist[3]</nowiki>'''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Type '''mylist'' '''inside square brackets''' ''zero '''and press '''Enter'''.

As we can see'''<nowiki> mylist[0]</nowiki>''' gives the first element''' spam'''

Type '''mylist '''''inside square brackets''' ''one '''and press '''Enter'''.

'''<nowiki>mylist[1] </nowiki>'''gives the second '''element'''.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Exercise1
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Pause the video. Try this exercise and then resume the video.

What happens when you type '''<nowiki>mylist[-1]</nowiki>'''.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''<nowiki>mylist[-1]</nowiki>'''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Switch to the '''terminal''' for solution

Type '''mylist '''''inside square brackets '''''minus one''''' ''and''' '''press '''Enter'''.

As you can see you get the last '''element''' which is '''one point two three four. '''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| slide

List in list

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| We can also create a '''list''' inside a '''list.'''

This property makes '''lists heterogeneous data structures'''.

This is the syntax for list inside a list.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''<nowiki>doublelist=[‘a’, [‘b’,’c’,’d’], 'and', </nowiki>5, 6, 7, 8] '''

'''<nowiki>Highlight [‘b’,’c’,’d’]</nowiki>'''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Let us include a '''list''' within a '''list''' for the variable '''doublelist'''.

Type the code as shown here:

Here '''b c d''' is a list in list which is represented within square brackets inside a list

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Type:'''<nowiki> doublelist[1] </nowiki>'''and press '''Enter'''

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Nowdonefetching the vale from index 0 is already explained, use some other index value as an example let us fetch some element from '''doublelist'''.

Type:''' doublelist '''''inside square brackets '''''one''' and press '''Enter'''

We can see the output as '''b c d '''within square brackets

This is because the index value '''one''' contains the list inside a list as its element.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Highlight according to narration
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Now let us try to access a specific element, say''' b''' from the list inside a list

For this type: '''doublelist''''' inside square brackets ''one ''inside square brackets '''''zero '''and press '''Enter'''.

Here the 1st parameter represents the index of the list inside the list in the main list

The second parameter represents the index value of '''b''' in the list inside the list

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Exercise2
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Pause the video. Try this exercise and then resume the video.

'''<nowiki>doublelist=[‘a’, [‘b’,’c’,’d’], 'and', </nowiki>5, 6, 7, 8] '''

# What is the command to get the element 'and' in the list doublelist?
# How would you get 'and' using negative indices?
# How would you get element 'd' from the list doublelist?

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Solution 2

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| The solution is on your screen

# '''doublelist '''''inside square brackets '''''two '''
# '''doublelist '''''inside square brackets '''''minus five '''
# '''doublelist '''''inside square brackets '''''one '''''inside square brackets '''''two '''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| '''slide len function'''

'''len''' function is used to check the number of '''elements''' in the '''list'''.

Syntax:

len(variable)

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| We can use '''len''' function to check the number of '''elements/length of '''in the '''list'''.

The syntax is: len ''inside'' ''parentheses ''variable

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''len(mylist) '''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Let us find the number of elements in '''mylist''' which we created earlier.

Switch to the''' terminal '''and clear the screen

Recall '''mylist''' by pressing up arrow key and press''' Enter.'''

Type '''len '''''inside parentheses '''''mylist '''and press '''Enter.'''

We get the length of mylist as '''four'''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| '''Slide Append function'''

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| We can append elements to the list using the '''append''' function.

This function will add the element to the end of the list.

The syntax is: variable ''dot'' '''append''' within ''parentheses element to be added.''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''mylist.append('sharp') '''

'''mylist.append(6)'''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Switch to the '''terminal'''

Now type

'''mylist''''' dot'' append ''inside parentheses within quotes''' ''sharp''' and''' '''press '''Enter'''.

'''mylist '''''dot'' append ''inside parentheses''' ''six'' '''''and''' '''press '''Enter.'''

Let us check the''' '''updated''' mylist.'''

Type''' mylist '''and''' '''press '''Enter '''

We can see '''mylist''' is '''appended''' with '''sharp''' and '''six''' at the end.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| '''slide del '''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| We can also remove '''elements''' from '''Lists'''.

There are two ways of doing it.

* One is by using the '''index '''with''' del''' keyword.
* Syntax is '''del '''variable ''inside square brackets element’s ''index value

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| '''slide remove'''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| * The other way is removing element by the value using remove function
* Syntax is '''variable '''''dot '''''remove '''''inside parentheses '''''element to be removed'''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| '''mylist '''

<nowiki>[IPython Terminal]</nowiki>

'''<nowiki>del mylist[1]</nowiki>'''

'''mylist '''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Switch to the''' terminal '''

Type '''mylist''' and press''' Enter '''to see the updated list

Type '''del '''''space '''''mylist '''''inside square brackets''''' one '''and press '''Enter.'''

The keyword '''del''' deletes the element at '''index''' one,

i.e the second element of the list,''' eggs'''.

Again type '''mylist''' and press''' Enter'''

We can see that the element '''eggs''' has been deleted from the list

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''mylist.remove(100) '''

'''mylist'''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Let us delete the element '''hundred''' from '''mylist''' list.

For this we can use the '''function''' '''remove'''.

Type '''mylist''''' dot '''''remove '''within parentheses''' hundred '''and press '''Enter.'''

Let us check the''' '''updated''' mylist.'''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[IPython Terminal]</nowiki>

'''mylist.append('spam') '''

Highlight spam
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| But what if the '''elements''' are repeated.

To check that, let’s do a small experiment.

Type

'''mylist''''' dot '''''append '''within parentheses within quotes '''spam '''and press''' enter'''

'''Type mylist '''and press''' Enter'''

Here is the''' '''updated''' mylist.'''

It contains the element '''spam''' twice.

One is at the start and the next is at the end of the list.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| '''mylist.remove('spam')'''

Type''' mylist '''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Now remove the element '''spam''' by typing:

'''mylist '''''dot '''''remove '''''inside parentheses inside quotes'' '''spam '''and press '''Enter.'''

Let us check''' '''updated''' mylist.'''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Pause for a while
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| We can see that only the first occurrence of ''''spam'''' has been removed.

The function '''remove''' removes the first occurrence of the element in the '''sequence'''.

Remember, the '''del '''keyword removes the element by index value.

'''remove '''function removes on the basis of element being passed on.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"|
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Using '''remove''' function, we can also remove an element with its index value

Let us try this with an example.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| <nowiki>[Ipython Terminal]</nowiki>

'''<nowiki>k = [1,2,1,3]</nowiki>'''

'''<nowiki>k.remove(k[2]) </nowiki>'''

'''k'''
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Type''' k '''''is equal to inside square brackets '''''one''''' comma '''''two''''' comma '''''one''''' comma '''''three'''

'''then type k '''''dot remove inside parentheses''''' k inside square brackets two '''and press''' Enter'''

Type''' k '''and''' '''press '''Enter '''

We can see the output as'''<nowiki> [2,1,3]. </nowiki>'''

Since it '''deletes''' the first occurrence of what is returned by '''k '''''inside square brackets''''' two''' which is''' one'''.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Exercise 3

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Pause the video. Try this exercise and then resume the video.

1. Delete the fourth element from the list doublelist.

2. Remove 'and' from the list doublelist.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Exercise 3

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| The solution is

# '''del doublelist''''' within square brackets''''' three '''
# '''doublelist '''''dot '''''remove '''''inside parentheses inside quotes''''' and'''

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Summary slide

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| This brings us to the end of this tutorial. In this tutorial, we have learnt to,''' '''

* '''Create:'''
** List with elements
** Empty list
** List within a list

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"|
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| We also learnt to,

* Find out the '''list''' length using '''len''' '''function'''.
* Access '''elements''' using their '''index''' numbers.
* Append '''elements''' to list using the '''function''' '''append'''.
* Delete '''element''' from list using the '''del''' and '''remove''' function

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Evaluation

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Here are some self assessment questions for you to solve

# How do you create an empty list?
# Can you have a list inside a list?
# How would you access the last element of a list without finding its length?

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Solutions

| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| And the answers,''' '''

# We create an empty list just by leaving the space inside the square brackets empty. '''myemptylist''' ''equal to open and close square brackets''.
# Yes, list can contain all the other data types, including list.
# Using negative indices, we can access the last element from the list.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide: Forum
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Please post your timed queries in this forum.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide: Fossee Forum
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Please post your general queries on Python in this forum.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide: Textbook Companion
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| FOSSEE team coordinates the TBC project.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide: Acknowledgement
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Spoken-tutorial is funded by NMEICT, MHRD, Govt. of India.

For more details, visit this website.

|-
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide

Thank You
| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| This is _________ from IIT Bombay signing off.

Thank You

|}

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Python-3.4.3/C2/Getting-started-with-Lists/English - Revision history

Nancyvarkey at 03:15, 8 September 2017

Trupti at 04:37, 7 September 2017

Trupti at 11:42, 6 September 2017

Trupti at 11:36, 6 September 2017

Trupti at 11:35, 6 September 2017

Trupti at 10:48, 6 September 2017

Trupti: Created page with "Python/C2/Getting Started with Lists/English '''Title of script''': '''Getting Started with Lists''' '''Author: Aditya Palaparthy''' '''Keywords: Python, IPython,''' '''lis..."

@@ Line 6: / Line 6: @@
 '''Keywords: Python, IPython,''' '''list, del, remove, append'''
 {| style="border-spacing:0;"
@@ Line 41: / Line 40: @@
 |-
-| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| doneAnimate the slideShow Slide
+| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide
 Pre-requisites
@@ Line 166: / Line 165: @@
 '''<nowiki>myemptylist = []</nowiki>'''
-| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Let us now create an '''empty list '''with no Can we use 'elements' instead of items. This is more in line with terms used when referring to a listelements.
+| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Let us now create an '''empty list '''with no elements.
 Type '''myemptylist '''''is equal to open and close square brackets ''and'' ''press '''Enter'''.
@@ Line 253: / Line 252: @@
 | style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Type:'''<nowiki> doublelist[1] </nowiki>'''and press '''Enter'''
-| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Nowdonefetching the vale from index 0 is already explained, use some other index value as an example let us fetch some element from '''doublelist'''.
+| style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Now let us fetch some element from '''doublelist'''.
 Type:''' doublelist '''''inside square brackets '''''one''' and press '''Enter'''
@@ Line 273: / Line 272: @@
 |-
 | style="background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.079cm;padding-right:0.191cm;"| Show Slide
 Exercise2