Difference between revisions of "Ruby/C2/Logical-and-other-Operators/English-timed"
From Script | Spoken-Tutorial
Sandhya.np14 (Talk | contribs) |
|||
Line 5: | Line 5: | ||
|- | |- | ||
| 00:02 | | 00:02 | ||
− | | Welcome to this | + | | Welcome to this '''Spoken Tutorial''' on '''Logical & Other Operators. ''' |
|- | |- | ||
| 00:06 | | 00:06 | ||
− | | In this tutorial we will learn | + | | In this tutorial, we will learn: |
|- | |- | ||
| 00:09 | | 00:09 | ||
− | | '''Logical Operators ''' | + | |* '''Logical Operators ''' |
|- | |- | ||
| 00:11 | | 00:11 | ||
− | |'''Parallel assignment''' and | + | |*'''Parallel assignment''' and |
|- | |- | ||
| 00:13 | | 00:13 | ||
− | | '''Range Operators ''' | + | |* '''Range Operators '''. |
|- | |- | ||
| 00:15 | | 00:15 | ||
− | |Here we are using | + | |Here we are using: |
|- | |- | ||
| 00:17 | | 00:17 | ||
− | | '''Ubuntu Linux''' version 12.04 | + | |* '''Ubuntu Linux''' version '''12.04''' |
|- | |- | ||
| 00:20 | | 00:20 | ||
− | | | + | |* ''' Ruby 1.9.3 ''' |
|- | |- | ||
| 00:23 | | 00:23 | ||
− | |To follow this tutorial you must know how to use ''' Terminal''' and '''Text editor''' in ''' Linux'''. | + | |To follow this tutorial, you must know how to use ''' Terminal''' and '''Text editor''' in '''Linux'''. |
|- | |- | ||
| 00:29 | | 00:29 | ||
− | |You must also be familiar with '''irb''' | + | |You must also be familiar with '''irb'''. |
|- | |- | ||
| 00:33 | | 00:33 | ||
− | | If not, for relevant tutorials, please visit our website | + | | If not, for relevant tutorials, please visit our website. |
|- | |- | ||
| 00:38 | | 00:38 | ||
− | |Logical | + | |'''Logical operators''' are also known as ''' Boolean operators''' |
|- | |- | ||
Line 61: | Line 61: | ||
|- | |- | ||
| 00:48 | | 00:48 | ||
− | |'''Logical Operators''' are | + | |'''Logical Operators''' are- |
|- | |- | ||
| 00:51 | | 00:51 | ||
− | | | + | |* double ampersand (&&) that is '''(and)''' |
|- | |- | ||
| 00:54 | | 00:54 | ||
− | | ''' | + | |* double '''pipe''' that is '''(or)''' |
|- | |- | ||
| 00:56 | | 00:56 | ||
− | | | + | |* Exclamation (!) that is '''(not)''' |
|- | |- | ||
| 01:00 | | 01:00 | ||
− | | | + | |* '&&' (double ampersand) and '''and''' evaluate to '''true''' only if both the expressions are '''true.''' |
|- | |- | ||
| 01:07 | | 01:07 | ||
− | |Second expression is evaluated only if the first is '''true. ''' | + | |Second expression is evaluated only if the first is '''true.''' |
|- | |- | ||
| 01:12 | | 01:12 | ||
− | | Difference in the two forms is | + | | Difference in the two forms is precedence. |
|- | |- | ||
Line 93: | Line 93: | ||
|- | |- | ||
| 01:20 | | 01:20 | ||
− | |Let's | + | |Let's see some examples now. |
|- | |- | ||
Line 101: | Line 101: | ||
|- | |- | ||
| 01:25 | | 01:25 | ||
− | | Open the ''' terminal''' by pressing '''Ctrl, Alt and T''' keys simultaneously. | + | | Open the ''' terminal''' by pressing '''Ctrl, Alt''' and '''T''' keys simultaneously. |
|- | |- | ||
| 01:31 | | 01:31 | ||
− | |Type | + | |Type "irb" and press '''Enter''' to launch '''interactive Ruby'''. |
|- | |- | ||
| 01:36 | | 01:36 | ||
− | | Type ''' 3 greater than 2 space double ampersand space 4 less than 5''' | + | | Type: ''' 3 greater than 2 space double ampersand space 4 less than 5'''. |
|- | |- | ||
| 01:47 | | 01:47 | ||
− | | Press ''' Enter''' | + | | Press ''' Enter'''. |
|- | |- | ||
Line 121: | Line 121: | ||
|- | |- | ||
| 01:53 | | 01:53 | ||
− | |Here, | + | |Here, expression1 that is 3>2 is '''true'''. |
|- | |- | ||
| 01:59 | | 01:59 | ||
− | | | + | |Expression 2 that is 4<5 is also '''true.''' |
|- | |- | ||
Line 133: | Line 133: | ||
|- | |- | ||
| 02:08 | | 02:08 | ||
− | |Now press '''Up Arrow''' key to get the previous command. | + | |Now, press '''Up-Arrow''' key to get the previous command. |
|- | |- | ||
|02:12 | |02:12 | ||
− | | And | + | | And replace the double ampersand symbol with the word "and". |
|- | |- | ||
| 02:17 | | 02:17 | ||
− | | Press '''Enter ''' | + | | Press '''Enter'''. |
|- | |- | ||
Line 149: | Line 149: | ||
|- | |- | ||
| 02:22 | | 02:22 | ||
− | | Now press up arrow key again to get the previous command. | + | | Now, press up-arrow key again to get the previous command. |
|- | |- | ||
| 02:27 | | 02:27 | ||
− | | In | + | | In expression1, replace greater-than sign with less-than, |
|- | |- | ||
| 02:32 | | 02:32 | ||
− | | | + | |press ''' Enter ''' |
|- | |- | ||
Line 165: | Line 165: | ||
|- | |- | ||
| 02:38 | | 02:38 | ||
− | |This is because | + | |This is because 3 < 2 is '''false.''' |
|- | |- | ||
Line 197: | Line 197: | ||
|- | |- | ||
| 03:15 | | 03:15 | ||
− | |''' 10 greater than 6 space double pipe space 12 less than 7''' | + | |Type: '''10 greater than 6 space double pipe space 12 less than 7''' |
|- | |- | ||
Line 209: | Line 209: | ||
|- | |- | ||
| 03:29 | | 03:29 | ||
− | |Here '''expression 1''' that is '''10>6''' is '''true'''. | + | |Here '''expression 1''', that is '''10>6''' is '''true'''. |
|- | |- | ||
Line 221: | Line 221: | ||
|- | |- | ||
| 03:42 | | 03:42 | ||
− | | Now press the '''Up Arrow''' key to get the previous command. | + | | Now press the '''Up-Arrow''' key to get the previous command. |
|- | |- | ||
| 03:46 | | 03:46 | ||
− | | In '''expression 1''' replace '''greater than | + | | In '''expression 1''' replace '''greater than''' sign with '''less than''' sign |
|- | |- | ||
| 03:52 | | 03:52 | ||
− | | | + | | and replace '''pipe''' symbol with the word '''or.''' |
|- | |- | ||
Line 409: | Line 409: | ||
|- | |- | ||
| 07:20 | | 07:20 | ||
− | |Now let's swap a and b. | + | |Now let's swap 'a' and 'b'. |
|- | |- | ||
| 07:23 | | 07:23 | ||
− | |To do so type | + | |To do so, type: |
|- | |- | ||
Line 425: | Line 425: | ||
|- | |- | ||
| 07:33 | | 07:33 | ||
− | | Press '''Up Arrow''' key twice to get the '''puts''' command and press '''Enter.''' | + | | Press '''Up-Arrow''' key twice to get the '''puts''' command and press '''Enter.''' |
|- | |- | ||
| 07:39 | | 07:39 | ||
− | | We get the output as | + | | We get the output as- |
|- | |- | ||
Line 437: | Line 437: | ||
|- | |- | ||
| 07:44 | | 07:44 | ||
− | | '''b=10 ''' | + | | '''b=10 '''. |
|- | |- | ||
Line 445: | Line 445: | ||
|- | |- | ||
| 07:50 | | 07:50 | ||
− | |The values in a '''range''' can be numbers, characters, | + | |The values in a '''range''' can be numbers, characters, '''string'''s or '''object'''s. |
|- | |- | ||
Line 485: | Line 485: | ||
|- | |- | ||
| 08:36 | | 08:36 | ||
− | |Type ''' | + | |Type: within brackets ''' 1 two dots 10''' then '''dot to underscore a''' |
|- | |- | ||
Line 513: | Line 513: | ||
|- | |- | ||
| 09:16 | | 09:16 | ||
− | |Type ''' | + | |Type: within brackets '''1 three dots 10''' then '''dot to underscore a'''. |
|- | |- | ||
Line 529: | Line 529: | ||
|- | |- | ||
| 09:39 | | 09:39 | ||
− | |Here the end value 10 is not included in the range. | + | |Here, the end value 10 is not included in the range. |
|- | |- | ||
Line 537: | Line 537: | ||
|- | |- | ||
| 09:50 | | 09:50 | ||
− | |Type ''' | + | |Type: within brackets '''1 two dots 10 three times equal to''' and then '''5'''. |
|- | |- | ||
Line 557: | Line 557: | ||
|- | |- | ||
| 10:17 | | 10:17 | ||
− | |In this tutorial, we have learnt | + | |In this tutorial, we have learnt: |
|- | |- | ||
| 10:20 | | 10:20 | ||
− | |'''Logical operator''' i.e | + | |'''Logical operator''' i.e double ampersand, double '''pipe''' and exclamation mark operators. |
|- | |- | ||
| 10:27 | | 10:27 | ||
− | |'''Parallel assignment''' Ex: a,b,c=10,20,30 | + | |'''Parallel assignment''' Ex: a, b, c = 10, 20, 30 |
|- | |- | ||
| 10:34 | | 10:34 | ||
− | |'''Range Operator | + | |'''Range Operator Inclusive operator '''(..) and Exclusive operator(...)'''. |
|- | |- | ||
| 10:39 | | 10:39 | ||
− | |As an assignment | + | |As an assignment, |
|- | |- | ||
| 10:41 | | 10:41 | ||
− | | | + | |declare two variables using '''parallel assignment''' and |
|- | |- | ||
| 10:45 | | 10:45 | ||
− | | | + | |check whether their sum lies between 20 and 50. |
|- | |- | ||
Line 589: | Line 589: | ||
|- | |- | ||
| 10:52 | | 10:52 | ||
− | |It | + | |It summarizes the Spoken Tutorial project. |
|- | |- | ||
Line 597: | Line 597: | ||
|- | |- | ||
| 11:00 | | 11:00 | ||
− | | | + | | The Spoken Tutorial project team: |
|- | |- | ||
| 11:03 | | 11:03 | ||
− | |Conducts workshops using spoken tutorials | + | |* Conducts workshops using spoken tutorials. |
|- | |- | ||
|11:05 | |11:05 | ||
− | |Gives certificates to those who pass an online test | + | |* Gives certificates to those who pass an online test. |
|- | |- | ||
| 11:09 | | 11:09 | ||
− | |For more details, please write to contact@spoken-tutorial.org | + | |For more details, please write to: |
+ | contact@spoken-tutorial.org | ||
|- | |- | ||
| 11:15 | | 11:15 | ||
− | | | + | | '''Spoken Tutorial''' project is a part of the '''Talk to a Teacher''' project. |
|- | |- | ||
Line 621: | Line 622: | ||
|- | |- | ||
| 11:25 | | 11:25 | ||
− | |More information on this | + | |More information on this mission is available at: |
+ | spoken hyphen tutorial dot org slash NMEICT hyphen Intro. | ||
|- | |- | ||
| 11:34 | | 11:34 | ||
− | |This script has been contributed by the spoken tutorial team IIT Bombay | + | |This script has been contributed by the spoken tutorial team, '''IIT Bombay'''. |
|- | |- | ||
| 11:38 | | 11:38 | ||
− | |And this is Shalini Nair signing off Thank you | + | |And this is Shalini Nair, signing off. Thank you. |
|} | |} |
Revision as of 10:51, 29 October 2015
Time | Narration |
00:02 | Welcome to this Spoken Tutorial on Logical & Other Operators. |
00:06 | In this tutorial, we will learn: |
00:09 | * Logical Operators |
00:11 | *Parallel assignment and |
00:13 | * Range Operators . |
00:15 | Here we are using: |
00:17 | * Ubuntu Linux version 12.04 |
00:20 | * Ruby 1.9.3 |
00:23 | To follow this tutorial, you must know how to use Terminal and Text editor in Linux. |
00:29 | You must also be familiar with irb. |
00:33 | If not, for relevant tutorials, please visit our website. |
00:38 | Logical operators are also known as Boolean operators |
00:42 | because they evaluate parts of an expression |
00:45 | and return a true or false value. |
00:48 | Logical Operators are- |
00:51 | * double ampersand (&&) that is (and) |
00:54 | * double pipe that is (or) |
00:56 | * Exclamation (!) that is (not) |
01:00 | * '&&' (double ampersand) and and evaluate to true only if both the expressions are true. |
01:07 | Second expression is evaluated only if the first is true. |
01:12 | Difference in the two forms is precedence. |
01:15 | Symbolic and that is&&(double ampersand) has higher precedence. |
01:20 | Let's see some examples now. |
01:22 | We will use irb for this. |
01:25 | Open the terminal by pressing Ctrl, Alt and T keys simultaneously. |
01:31 | Type "irb" and press Enter to launch interactive Ruby. |
01:36 | Type: 3 greater than 2 space double ampersand space 4 less than 5. |
01:47 | Press Enter. |
01:49 | We get the output as true. |
01:53 | Here, expression1 that is 3>2 is true. |
01:59 | Expression 2 that is 4<5 is also true. |
02:03 | Since both the expressions are true, we get output as true. |
02:08 | Now, press Up-Arrow key to get the previous command. |
02:12 | And replace the double ampersand symbol with the word "and". |
02:17 | Press Enter. |
02:19 | We get the same result. |
02:22 | Now, press up-arrow key again to get the previous command. |
02:27 | In expression1, replace greater-than sign with less-than, |
02:32 | press Enter |
02:35 | We get the output as false. |
02:38 | This is because 3 < 2 is false. |
02:43 | Since the first expression is false, the second expression will not be evaluated. |
02:49 | So, we get output as false. |
02:53 | double pipe and or evaluate to true, if either expression is true. |
02:59 | Second expression is evaluated only if first is false. |
03:04 | Difference in the two forms is precedence. |
03:07 | Symbolic or i.e double pipe has higher precedence. |
03:11 | Now, let's try some examples. |
03:15 | Type: 10 greater than 6 space double pipe space 12 less than 7 |
03:23 | Press Enter. |
03:26 | We get output as true. |
03:29 | Here expression 1, that is 10>6 is true. |
03:35 | Since the first expression is true , second expression will not be evaluated. |
03:40 | So, we get the output as true. |
03:42 | Now press the Up-Arrow key to get the previous command. |
03:46 | In expression 1 replace greater than sign with less than sign |
03:52 | and replace pipe symbol with the word or. |
03:57 | Press Enter. |
04:00 | Here, expression1 that is 10<6 is false. |
04:05 | Expression 2 that is 12<7 is also false. |
04:10 | Since both the expressions are false, we get output as false. |
04:15 | ! (exclamation mark ) and not operators return the opposite value of the expression |
04:20 | If the expression is true, exclamation mark operator will return a false value. |
04:27 | It will return true if the expression is false. |
04:30 | Difference in the two forms is precedence. |
04:33 | Symbolic not that is (!) has higher precedence. |
04:37 | Let's try out the not operator. |
04:40 | First type 10 double equal to 10 |
04:45 | Press Enter |
04:47 | We get the output as true. |
04:50 | To invert the result of above expression, |
04:53 | let's add the not operator before the expression. |
04:57 | Type Exclamation mark within brackets 10 double equal to 10 |
05:04 | Press Enter. |
05:06 | We get the output as false. |
05:10 | Press Ctrl+L simultaneously to clear the irb console. |
05:15 | Next, let us learn about parallel assignment. |
05:20 | Multiple variables can be initialized with a single line of Ruby code, through parallel assignment. |
05:26 | Let's switch to the terminal. |
05:29 | Let's declare three variables a, b, c using parallel assignment. |
05:36 | Type a comma b comma c equal to 10 comma 20 comma 30 |
05:45 | and press Enter. |
05:47 | Here, 10 will be assigned to variable a |
05:52 | 20 will be assigned to variable b |
05:54 | 30 will be assigned to variable c |
05:56 | The right hand side acts as an array. |
06:01 | If we list multiple variables on the left hand side, then the array is unpacked and assigned into the respective variables. |
06:10 | We will learn about arrays in detail in the upcoming tutorials. |
06:14 | For now, let's check whether the assignment is done properly. |
06:20 | Type a and press Enter. |
06:23 | Value 10 stored in variable a is displayed. |
06:28 | Type b and press Enter. |
06:31 | We get 20 |
06:33 | Type c and press Enter. |
06:37 | 30 is displayed. |
06:40 | Parallel assignment is also useful for swapping the values stored in two variables. |
06:45 | Let us swap the values of variables a and b. |
06:50 | Type puts space within double quotes a equal to hash within curly brackets a comma within double quotes b equal to hash within curly brackets b |
07:11 | Press Enter. |
07:13 | We get the output as a=10 |
07:16 | b=20 |
07:20 | Now let's swap 'a' and 'b'. |
07:23 | To do so, type: |
07:25 | a comma b equal to b comma a |
07:31 | Press Enter. |
07:33 | Press Up-Arrow key twice to get the puts command and press Enter. |
07:39 | We get the output as- |
07:41 | a=20 |
07:44 | b=10 . |
07:47 | We will now learn about range in Ruby. |
07:50 | The values in a range can be numbers, characters, strings or objects. |
07:58 | Ranges are used to express a sequence. |
08:02 | Sequence range is used to create a range of successive values. |
08:06 | It consists of a start value, range of values and an end value. |
08:13 | (..) two dot operator creates inclusive range. |
08:16 | (...) three dot operator creates an exclusive range. |
08:20 | Ranges are used to identify whether a value falls within a particular range, too. |
08:26 | We do this using (===) the equality operator. |
08:30 | Let us try out some examples on ranges. |
08:33 | Let's switch to terminal. |
08:36 | Type: within brackets 1 two dots 10 then dot to underscore a |
08:46 | Two dot operator creates inclusive range. |
08:50 | Inclusive operator includes both begin and end values in a range. |
08:57 | Here to_a method is used to convert a range to a list. |
09:03 | Press Enter. |
09:05 | Here you can see the values 1 and 10 are included in the range. |
09:11 | Now we will see an exclusive range operator. |
09:16 | Type: within brackets 1 three dots 10 then dot to underscore a. |
09:27 | Three dot operator creates an exclusive range. |
09:31 | Exclusive range operator excludes the end value from the sequence. |
09:37 | Press Enter. |
09:39 | Here, the end value 10 is not included in the range. |
09:45 | Now let's check whether 5 lies in the range of 1 to 10. |
09:50 | Type: within brackets 1 two dots 10 three times equal to and then 5. |
10:00 | Press Enter. |
10:02 | Equality operator is used to check whether a value lies in the range. |
10:07 | We get the output as true since 5 lies in the range 1 to 10. |
10:14 | This brings us to the end of this Spoken Tutorial. |
10:17 | In this tutorial, we have learnt: |
10:20 | Logical operator i.e double ampersand, double pipe and exclamation mark operators. |
10:27 | Parallel assignment Ex: a, b, c = 10, 20, 30 |
10:34 | Range Operator Inclusive operator (..) and Exclusive operator(...). |
10:39 | As an assignment, |
10:41 | declare two variables using parallel assignment and |
10:45 | check whether their sum lies between 20 and 50. |
10:49 | Watch the video available at the following link. |
10:52 | It summarizes the Spoken Tutorial project. |
10:56 | If you do not have good bandwidth, you can download and watch it. |
11:00 | The Spoken Tutorial project team: |
11:03 | * Conducts workshops using spoken tutorials. |
11:05 | * Gives certificates to those who pass an online test. |
11:09 | For more details, please write to:
contact@spoken-tutorial.org |
11:15 | Spoken Tutorial project is a part of the Talk to a Teacher project. |
11:19 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
11:25 | More information on this mission is available at:
spoken hyphen tutorial dot org slash NMEICT hyphen Intro. |
11:34 | This script has been contributed by the spoken tutorial team, IIT Bombay. |
11:38 | And this is Shalini Nair, signing off. Thank you. |