Python-3.4.3/C3/Getting-started-with-tuples/English-timed
From Script | Spoken-Tutorial
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| 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.
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| 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.
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| 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. |
