Python-3.4.3/C3/Conditional-Statements/English-timed
From Script | Spoken-Tutorial
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| 00:01 | Welcome to the spoken tutorial on Conditional statements. |
| 00:06 | In this tutorial, we will learn to use
if/else blocks |
| 00:13 | if/elif/else blocks
Ternary conditional statement and Pass statement |
| 00:22 | To record this tutorial, I am using
Ubuntu Linux 16.04 operating system |
| 00:30 | Python 3.4.3
and IPython 5.1.0 |
| 00:37 | To practice this tutorial, you should know how to use
basic data types and operators |
| 00:46 | strings and Input/Output statements |
| 00:50 | If not, see the relevant Python tutorials on this website. |
| 00:55 | First let us learn about if condition. |
| 00:59 | if condition is used to decide whether to execute the statements inside the if block or not.
Here is the syntax. |
| 01:10 | Next we will see about if else condition. |
| 01:14 | When the test condition is true, it will execute the body of if. |
| 01:20 | If the condition is False, body of the else is executed. |
| 01:25 | Note that, if and else statements end with a colon. |
| 01:30 | This denotes the beginning of the code block of True or False condition. |
| 01:36 | All the statements inside a code block are indented by 4 spaces. |
| 01:42 | Let us start ipython.
Open the terminal. |
| 01:48 | Type ipython3 and press Enter. |
| 01:53 | From here onwards, remember to press the Enter key after typing every command on the terminal. |
| 02:00 | Now let us check if an entered number is even or not. |
| 02:05 | Type, num is equal to int inside brackets input open and close brackets |
| 02:14 | Enter 4 and press Enter |
| 02:18 | Type, if num percentage 2 equal to equal to 0 colon |
| 02:26 | print inside brackets inside single quotes Even |
| 02:32 | Press backspace four times and type, else colon |
| 02:39 | print inside brackets inside single quotes Odd |
| 02:44 | Press Enter twice to get the output.
As expected, it displays Even as output. |
| 02:53 | Note that, the statements inside a code block are indented by 4 spaces automatically. |
| 03:00 | Next we will see another conditional statement called elif. |
| 03:05 | All the syntax and rules for elif are same as if/else statements. |
| 03:11 | In if/else, only one condition is checked. |
| 03:15 | But in elif statement multiple conditions can be checked. |
| 03:20 | For example,
The first block of code is executed as soon as condition one evaluates to True. |
| 03:28 | All the subsequent conditions in elif ladder are not checked. |
| 03:33 | The else block gets executed if all the conditions in if and elif ladder are evaluated to False. |
| 03:42 | Let us understand if/elif/else ladder with an example. |
| 03:48 | Type, a is equal to minus 3
We have a variable a which holds integer value as -3. |
| 03:58 | Type as shown.
This program will print "positive" if a is positive, |
| 04:06 | "negative" if it is negative or "zero" if the above conditions are evaluated to False |
| 04:15 | Press Enter twice to see the output. |
| 04:20 | We can also have any number of elif conditions within an if/elif/else statements. |
| 04:27 | For example, based on the type of user the corresponding operations are performed using elif. |
| 04:35 | Pause the video.
Try this exercise and then resume the video. |
| 04:41 | Given a number, num as input.
Write an if else block to print num, if it is divisible by 10, else print 10 asterisk num. |
| 04:53 | The solution is on your screen. |
| 04:57 | Next let us learn about ternary operator. |
| 05:01 | Ternary operator allows to test a condition in a single line replacing the multiline if-else. |
| 05:08 |
It can reduce the code size and increase the readability of the code. Here is the syntax. |
| 05:16 | Let us write a ternary conditional statement to find the largest of two numbers. |
| 05:23 | Type, a is equal to 4 |
| 05:26 | b is equal to 2 |
| 05:30 | large underscore num is equal to a if a greater than b else b |
| 05:39 | print inside brackets large underscore num |
| 05:44 | We got the required output. |
| 05:47 | Pause the video.
Try this exercise and then resume the video. |
| 05:53 | Given a number, n as input.
Write a ternary operator to print n, if it is divisible by 10, else print 10 asterisk n. |
| 06:05 | The solution is on your screen. |
| 06:09 | Next we will learn about pass statement. |
| 06:13 | The pass statement acts as a null operation (i.e) nothing happens when it executes. |
| 06:21 | It works as a placeholder for a block of code. |
| 06:25 | It is used in a code block where actual code implementation is not known yet. |
| 06:32 | Let us understand the pass statement with an example. |
| 06:37 | Type a is equal to 11 |
| 06:41 | Then type as shown. |
| 06:44 | If a divided by 2 equals to zero, if block is executed.
Else no operation is performed. |
| 06:54 | Press Enter key twice to get the output.
Here a divided by 2 is not 0. |
| 07:02 | So no operation is performed and nothing is displayed as output. |
| 07:08 | This brings us to the end of the tutorial.
Let us summarize. |
| 07:14 | In this tutorial, we have learnt the conditional statements such as,
if/else statement |
| 07:22 | if/elif/else statement |
| 07:25 | Ternary conditional statement and Pass statement |
| 07:30 | Here are some self assessment questions for you to solve. |
| 07:35 | First. Given a variable t. |
| 07:38 | Print Good Morning if it is less than 12, otherwise print Hello. Use if else statement. |
| 07:47 | Second. Convert the below if else code into ternary conditional statement. |
| 07:56 | And the answers,
First. The following code gives the required output. |
| 08:03 | Second. Use the following statement to convert the if else code into a ternary statement |
| 08:11 | Please post your timed queries in this forum. |
| 08:15 | Please post your general queries on Python in this forum. |
| 08:20 | FOSSEE team coordinates the TBC project. |
| 08:24 | Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India.
For more details, visit this website. |
| 08:34 | This is Priya from IIT Bombay signing off. Thanks for watching. |
