Python-3.4.3/C3/Sequence-datatypes/English-timed

Time	Narration
00:01	Welcome to the tutorial on Sequence data types.
00:06	In this tutorial, we will learn about- Sequence Data types such as List , String and Tuple
00:16	Accessing the above data types using index
00:20	Convert list to tuple and vice-versa and
00:24	Convert string to list and vice-versa.
00:28	To record this tutorial, I am using Ubuntu Linux 16.04 operating system
00:35	Python 3.4.3 and IPython 5.1.0
00:42	To practise this tutorial, you should know how to run basic Python commands on the ipython console
00:50	If not, see the relevant Python tutorials on this website.
00:55	Sequence data types are those in which elements are kept in a sequential order.
01:01	The elements are accessed using index numbers.
01:05	The sequence data types in Python are list , string and tuple
01:14	First let us understand what is list.
01:18	List is a container that holds a number of objects in the given order.
01:24	For example: num underscore list is equal to inside square brackets 1, 2, 3, 4
01:32	A list can store data of any type.
01:36	List is most useful when storing data of identical type. Examples: Name of books in a library and Passengers on a flight
01:49	Let us start ipython3 pylab. Open the terminal.
01:54	Type ipython3 space hyphen hyphen pylab and press Enter.
02:02	From here onwards, remember to press the Enter key after typing every command on the terminal.
02:09	Now we will create our first list. Type, num underscore list is equal to inside square brackets 1, 2, 3, 4
02:20	Type, num underscore list
02:24	Comma-separated items enclosed in square brackets constitute a list.
02:30	We can have a list something like this.
02:34	Type, var underscore list is equal to inside square brackets 1, 1.2, inside square brackets 1,2
02:45	Type, var underscore list
02:48	Now let us look at another sequence data type, strings.
02:53	Type greeting underscore string is equal to inside double quotes hello
03:00	Type greeting underscore string
03:04	It is now a string variable with the value hello.
03:08	Python strings can actually be defined in three different ways as follows.
03:14	k is equal to inside single quotes Single quote
03:19	l is equal to inside double quotes Let's see how to include a single quote
03:26	m is equal to inside triple quotes This is another “example” for string
03:33	Here single, double and triple quotes are used as delimiters.
03:40	The last in the list of sequence data types is tuple.
03:45	Type person underscore tuple is equal to inside brackets 17 comma inside double quotes Ram comma 56.8
03:56	This tuple contains age,name and weight of a person.
04:01	To create a tuple we use normal brackets unlike square brackets for list.
04:07	Next, let us see how to access the list using index numbers.
04:12	Type, num underscore list inside square brackets 2
04:18	num underscore list inside square brackets -1
04:23	Recall that, the index of the elements starts with 0 instead of 1.
04:29	Now let us access the string elements.
04:33	Type, greeting underscore string inside square brackets 1
04:39	greeting underscore string inside square brackets 3
04:44	greeting underscore string inside square brackets -2
04:49	We can see that the output is displayed as per the index value.
04:54	Next let us access tuple elements.
04:58	Type person underscore tuple inside square brackets 2
05:04	person underscore tuple inside square brackets -3
05:10	The output shows the weight and age of the person as per the index value.
05:16	Next, we will see about how to add sequences.
05:21	Type num underscore list plus var underscore list
05:27	Addition gives a new sequence containing both the sequences.
05:32	Likewise, we will do for string data type.
05:36	Type a underscore string is equal to inside double quotes space another string
05:44	greeting underscore string plus a underscore string
05:49	We can see that both the strings are added now.
05:53	Next we will see for tuple.
05:56	Type, t2 is equal to inside brackets inside double quotes Student comma
06:04	Adding a comma after Student is important to make t2 a tuple.
06:10	Type, person underscore tuple plus t2
06:15	Now we can see that Student is added to the tuple.
06:20	Next let us see how to find the length of a variable.
06:25	We use len function for that. Type, len inside brackets num underscore list
06:34	The output shows the number of objects of the list.
06:38	Type, len inside brackets greeting underscore string
06:44	len inside brackets person underscore tuple
06:49	Next we will learn to check the presence of an element using the 'in' keyword
06:55	Type, 3 in num underscore list
06:59	Inside single quotes H in greeting underscore string
07:04	Inside double quotes Sita in person underscore tuple
07:09	We can see that the output displays True and False accordingly.
07:14	Next we will find the maximum and minimum values.
07:19	We use max function to find the maximum value.
07:23	Type, max inside brackets num underscore list
07:28	The min function is used to find minimum value.
07:33	Type, min inside brackets greeting underscore string
07:38	For string data type, ASCII value is used to get the maximum and minimum values.
07:45	Next we will find the sum of a list. Type, sum inside brackets num underscore list
07:54	So far we have talked about many similar features of list, string and tuple.
08:01	But there are many important features in list that differ from string and tuple.
08:08	Let us see them using some examples.
08:12	Type, num underscore list inside square brackets 1 is equal to 9
08:20	num underscore list Here the value at index 1 is assigned to 9.
08:28	Type, greeting underscore string inside square brackets 1 is equal to inside single quotes k
08:37	The first command executes without a problem. But there is an error in the second one.
08:45	Now let us try it in tuple. Type person underscore tuple inside square brackets 0 is equal to 23
08:56	We can see the same error again. This is because strings and tuples cannot change the value at a particular index.
09:05	But we can convert list to tuple and tuple to list.
09:10	First let us learn to convert list to tuple. Type as shown
09:19	t is equal to tuple inside brackets list underscore tuple Tuple function converts the list to tuple.
09:29	Type, t Now the list is successfully converted to tuple.
09:36	Next let us learn to convert tuple to list. Type as shown.
09:44	Type, l is equal to list inside brackets tuple underscore list
09:51	List function converts the tuple to list.
09:55	Type, l
09:58	Now the tuple is successfully converted to list.
10:02	Next let us learn to convert string to list and list to string. Let us say we have the following string.
10:12	Type otherstring dot split inside brackets inside single quotes comma
10:19	This produces a list with the string split at comma.
10:23	join function does the opposite. It joins a list to make a string.
10:29	Let us say we have the following list.
10:33	Type, inside single quotes comma dot join inside brackets otherlist
10:41	Thus we get a list joined on commas.
10:45	Similarly we can do on spaces.
10:49	Type as shown.
10:52	Note that the list has to be a list of strings to apply join operation.
10:58	Type, inside single quotes space dot join inside brackets spacestring
11:06	We can see that the list is joined on spaces.
11:10	Pause the video. Try this exercise and then resume the video.
11:16	Check if 3 is an element of the following list.
11:21	Change the third element in the list to 21.
11:25	Switch to the terminal for the solution.
11:29	Type, l is equal to inside square brackets 1,7,5,3,4
11:37	3 in l The output is True. So the element 3 is in the list.
11:45	Type, l inside square brackets 3 is equal to 21
11:51	Type, l We can see that the element 3 is changed to 21.
11:58	Pause the video. Try this exercise and then resume the video.
12:04	Convert the string "Elizabeth is queen of England" to "Elizabeth is queen"
12:10	Switch to the terminal for the solution.
12:14	Type s is equal to inside double quotes Elizabeth is queen of england
12:21	stemp is equal to s.split open and close brackets
12:28	s is equal to inside single quotes space dot join inside brackets stemp inside square brackets colon 3
12:40	Type, s We got the required output.
12:46	This brings us to the end of this tutorial.
12:50	In this tutorial, we have learnt to, Use the sequence data types such as List, String and Tuple
12:59	Split and join a list using split and join functions respectively
13:05	Convert list to tuple and vice-versa and
13:09	Convert string to tuple and vice-versa
13:13	Here are some self assessment questions for you to solve
13:17	First. What is the major difference between tuple and list?
13:22	Second. Split the below string on whitespaces
13:27	And the answers, First. The major difference between tuple and list is that,
13:34	Tuple cannot change the value at a particular index
13:38	But list can change the value
13:41	Tuple is used to store data related to an item
13:46	But list is typically used to store items of identical type
13:51	Second. To split the string on whitespace, we use the split function without any argument
13:58	Please post your timed queries in this forum.
14:02	Please post your general queries on Python in this forum.
14:07	FOSSEE team coordinates the TBC project.
14:11	Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India. For more details, visit this website.
14:19	This is Priya from IIT Bombay signing off. Thanks for watching.

Contributors and Content Editors

PoojaMoolya