Python-3.4.3/C3/Getting-started-with-tuples/English-timed

Time	Narration
00:01	Welcome to the spoken tutorial on Getting Started with tuples.
00:07	In this tutorial we will: Understand what tuples are
00:12	Compare tuples with lists
00:15	Know why they are needed and Learn to use them.
00:21	To record this tutorial, I am using Ubuntu Linux 16.04 operating system
00:29	Python 3.4.3 and IPython 5.1.0
00:36	To practise this tutorial, you should know how to run basic Python commands on the ipython console and use lists
00:47	If not, see the relevant Python tutorials on this website.
00:53	First we will learn about tuples.
00:57	Tuple is a collection of elements similar to a list.
01:02	Tuple uses parentheses, whereas list uses square brackets.
01:08	Elements of a tuple cannot be changed once it is assigned.
01:13	But in a list, elements can be changed.
01:17	Here are few examples for declaring tuples.
01:21	Inside brackets 1, 2.5 is a tuple with two elements.
01:27	The same can be declared as 1, 2.5.
01:32	Inside brackets 1 comma is a tuple with one element.
01:37	The same can be declared as 1 comma
01:41	Inside brackets again inside brackets 1 comma and outside bracket a comma is a tuple with one tuple as element.
01:52	The same can be declared as inside brackets 1 comma and outside bracket a comma.
01:59	Let us start ipython. Open the terminal.
02:04	Type ipython3 and press Enter.
02:10	From here onwards, remember to press the Enter key after typing every command on the terminal.
02:17	Let's learn to create a tuple. Type, t is equal to inside brackets 1 comma 2.5 comma inside double quotes hello comma minus 4 comma inside double quotes world comma 1.24 comma 5
02:38	Type, t It is similar to list except that parentheses are used instead of square brackets.
02:47	At least one comma is mandatory for a tuple.
02:51	The brackets are optional, but should be added for clarity.
02:56	The items in the tuple can be accessed by their index positions.
03:02	Type, t inside square brackets 3
03:07	Type, t inside square brackets 1 colon 5 colon 2 It prints the corresponding slice.
03:16	Now we try to change an element in the tuple.
03:20	Type, t inside square brackets 2 is equal to inside double quotes Hello
03:28	We can see that, it raises an error saying 'tuple object does not support item assignment'.
03:35	It shows, elements of a tuple cannot be changed after it is created. This is called immutability.
03:44	We can iterate over tuples like lists.
03:48	Type, for x in t colon print inside brackets x
03:57	It prints each element of the tuple t.
04:01	Pause the video. Try this exercise and then resume the video.
04:07	Let us look at a simple problem of swapping values.
04:12	Given, a is equal to 5 and b is equal to 7, swap the values of a and b.
04:20	Switch to the terminal for the solution.
04:24	Type, a is equal to 5
04:28	b is equal to 7
04:32	Then type, a Type, b
04:38	We now create a variable say, temp and swap the values using this variable.
04:45	Type temp is equal to a
04:49	a is equal to b
04:53	b is equal to temp
04:57	Then type, a Type, b
05:02	We can see that the values are successfully swapped now. But this is the traditional approach.
05:10	Now let us do it in the Python way.
05:14	Type a is equal to 5 b is equal to 7
05:21	a, b is equal to b, a
05:27	Now we will check whether the values are swapped.
05:31	Type, a Type, b
05:36	We can see that the values are swapped easily.
05:40	We can also do this for different datatypes.
05:44	Type, a is equal to 2.5
05:49	b is equal to inside double quotes hello a, b is equal to b, a
05:59	Now to check the values, type, a Type, b
06:07	This is possible because of the immutability of tuples.
06:12	This is called tuple packing and unpacking.
06:16	When you type, a comma b is equal to b comma a
06:21	First, the values of b and a are packed into a tuple on the right side. Then it is unpacked into the variables a and b.
06:32	Let us first see about tuple packing.
06:36	Type, 5 comma We can see a tuple with one element.
06:43	Type, 5 comma inside double quotes hello comma 2.5
06:49	Now it is a tuple with three elements.
06:53	When we type two or more elements separated by commas, those elements are packed into a tuple.
07:01	Immutability of tuples ensures that the values are not changed during the packing and unpacking.
07:09	This brings us to the end of this tutorial. Let us summarize.
07:15	In this tutorial, we have learnt about, Tuples
07:21	Similarities of tuples with lists
07:25	Immutability of tuples and Concept of Packing and unpacking of tuples.
07:32	Here are some self assessment questions for you to solve.
07:36	First. Define a tuple containing two values as given below. The first value is integer 4 and the second value is float 2.5.
07:50	Second. If we type, a is equal to 5 comma then what is the datatype of a?
07:58	Third. If we type, a is equal to inside brackets 2 comma 3 a inside square brackets 0 comma a inside square brackets 1 is equal to inside brackets 3 comma 4 What is the output?
08:16	And the answers, First. A tuple is defined by enclosing parentheses around a sequence of items separated by commas. Hence, we write our tuple as, inside brackets 4 comma 2.5
08:32	Second. Since the given data is 5 followed by a comma, it is a tuple
08:39	Third. The given operation will give a TypeError because tuples are immutable.
08:46	Please post your timed queries in this forum.
08:50	Please post your general queries on Python in this forum.
08:55	FOSSEE team coordinates the TBC project.
08:59	Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India. For more details, visit this website.
09:09	This is Priya from IIT Bombay signing off. Thanks for watching.

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