Linux-AWK/C2/Conditional-statements-in-awk/English-timed
From Script | Spoken-Tutorial
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| 00:01 | Hello and welcome to this spoken tutorial on conditional statements in awk. |
| 00:07 | In this tutorial, we will learn about- if, else, else if in awk. |
| 00:15 | We will do this through some examples. |
| 00:19 | To record this tutorial, I am using:
Ubuntu Linux 16.04 Operating System and gedit text editor 3.20.1 |
| 00:32 | You can use any text editor of your choice. |
| 00:36 | To practice this tutorial, you should have gone through the previous awk tutorials on our website. |
| 00:43 | You should have familiarity with any programming language like C or C++. |
| 00:50 | If not, then please go through the corresponding tutorials on our website. |
| 00:56 | The files used in this tutorial are available in the Code Files link on this tutorial page.
Please download and extract them. |
| 01:06 | A conditional statement allows us to check a specified condition before performing an action. |
| 01:14 | Let’s learn how conditional statements like if, else, else-if work in awk. |
| 01:22 | Like any programming language, the syntax of 'if -else' statement is: |
| 01:28 | if conditional-expression1 is true then perform action1. |
| 01:34 | else if conditional-expression2 is true then perform action 2. |
| 01:41 | A number of else if statements may follow after this. |
| 01:46 | At the end, if none of the specified conditional expressions are true then perform action n. |
| 01:54 | The else and else-if portions are optional.
Let us go through an example. |
| 02:02 | We will use the same awkdemo.txt file that we have used earlier. |
| 02:10 | Say, we need to give 50% increment in stipend to the students getting more than 8000 rupees. |
| 02:19 | Let us create an awk file for this condition. |
| 02:23 | Type the following code as shown, in a text editor and save it as cond dot awk.
I have already done this. |
| 02:34 | The same file is also available in the Code Files link. |
| 02:39 | In this code, we have set the Output Field Separator as colon. |
| 02:45 | The first print statement prints the field headings. |
| 02:50 | Next, the 'if' statement will check whether the value of the 6th field is greater than 8000. |
| 02:58 | If yes, the second print statement will get executed. |
| 03:03 | $6 into 1.5 inside this print statement will multiply the 6th field value by 1.5 . |
| 03:13 | Let’s execute this code now. |
| 03:16 | Open the terminal by pressing CTRL, ALT and T keys. |
| 03:22 | Go to the folder in which you downloaded and extracted the Code Files using 'cd' command. |
| 03:29 | Now, type: awk space hyphen capital F pipe symbol within double quotes space hyphen small f space cond dot awk space awkdemo dot txt.
Press Enter. |
| 03:49 | The output shows only one student’s record with the incremented stipend who fulfilled the condition. |
| 03:57 | Now, suppose the rule changes: 50% increment in stipend for students who get more than 8000 rupees. |
| 04:07 | Otherwise, give 30% increment.
How can we do that? |
| 04:13 | We need to add an 'else' block. |
| 04:16 | Switch to the cond dot awk file once again. |
| 04:21 | Let us add the following line of code.
Before the last closing curly brace press Enter. |
| 04:30 | else press Enter. |
| 04:33 | print space dollar 2 comma dollar 6 comma dollar 6 into 1.3 |
| 04:42 | Save the file and switch to the terminal. |
| 04:46 | Press the up-arrow key to get the previously executed command and press Enter. |
| 04:53 | Observe the output now.
Yojna Chaudhury was previously getting 1000. Now she is getting 1300. |
| 05:04 | Let’s change the rules again.
50% increment for student getting more than 8000 rupees. |
| 05:13 | 40% increment for student getting more than 4000 rupees.
Otherwise, give 30% increment. |
| 05:23 | Switch to the code. Update the code as shown. |
| 05:29 | Save the file and switch to the terminal. |
| 05:33 | Let me clear the terminal. |
| 05:36 | Now, press up-arrow key to get the previously executed command and press Enter. |
| 05:44 | This time, notice that the student Mira Nair has got 40% increment. |
| 05:51 | This brings us to the end of this tutorial. |
| 05:54 | Let us summarize. In this tutorial, we learnt about Conditional statements like:
if , else, else if in awk. |
| 06:05 | As an assignment, give grades according to the rules:
If mark is greater than equal to 90, grade will be A. |
| 06:15 | If mark is greater than equal to 80 but less than 90, grade will be B. |
| 06:23 | If mark is greater than equal to 70 but less than 80, grade will be C. |
| 06:30 | If mark is greater than equal to 60 but less than 70, grade will be D.
Otherwise, grade will be F. |
| 06:41 | The video at the following link summarises the Spoken Tutorial project.
Please download and watch it. |
| 06:49 | The Spoken Tutorial Project team conducts workshops using spoken tutorials.
And, gives certificates on passing online tests. |
| 06:58 | For more details, please write to us. |
| 07:02 | Do you have questions in THIS Spoken Tutorial?
Please visit this site. |
| 07:08 | Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.
More information on this mission is available at this link. |
| 07:20 | The script has been contributed by Antara. And this is Praveen from IIT Bombay, signing off.
Thanks for joining. |
