Difference between revisions of "PERL/C2/Array-functions/English-timed"
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{| border=1 | {| border=1 | ||
− | + | |'''Time''' | |
− | + | |'''Narration''' | |
|- | |- | ||
− | | 00 | + | | 00:01 |
|Welcome to the spoken tutorial on '''Array Functions''' in '''Perl''' | |Welcome to the spoken tutorial on '''Array Functions''' in '''Perl''' | ||
|- | |- | ||
− | | 00 | + | | 00:06 |
| In this tutorial, we will learn about '''Array functions''' in '''Perl''', like | | In this tutorial, we will learn about '''Array functions''' in '''Perl''', like | ||
|- | |- | ||
− | |00 | + | |00:11 |
|'''push ''' | |'''push ''' | ||
|- | |- | ||
− | |00 | + | |00:11 |
| '''pop''' | | '''pop''' | ||
|- | |- | ||
− | |00 | + | |00:12 |
|'''shift''' | |'''shift''' | ||
|- | |- | ||
− | | 00 | + | | 00:14 |
| '''unshift ''' | | '''unshift ''' | ||
|- | |- | ||
− | | 00 | + | | 00:15 |
|'''split''' | |'''split''' | ||
|- | |- | ||
− | | 00 | + | | 00:16 |
| '''splice ''' | | '''splice ''' | ||
|- | |- | ||
− | | 00 | + | | 00:17 |
| and ''' join''' | | and ''' join''' | ||
|- | |- | ||
− | | 00 | + | | 00:18 |
| '''sort''' | | '''sort''' | ||
|- | |- | ||
− | | 00 | + | | 00:19 |
| '''qw''' | | '''qw''' | ||
|- | |- | ||
− | |00 | + | |00:20 |
|I am using ''' Ubuntu Linux12.04''' operating system and '''Perl 5.14.2''' | |I am using ''' Ubuntu Linux12.04''' operating system and '''Perl 5.14.2''' | ||
|- | |- | ||
− | |00 | + | |00:28 |
|I will also be using the '''gedit''' Text Editor. | |I will also be using the '''gedit''' Text Editor. | ||
|- | |- | ||
− | | 00 | + | | 00:32 |
| You can use any text editor of your choice. | | You can use any text editor of your choice. | ||
|- | |- | ||
− | |00 | + | |00:36 |
|You should have basic knowledge of ''' Variables, Data Structures''' and '''Arrays''' in '''Perl''' | |You should have basic knowledge of ''' Variables, Data Structures''' and '''Arrays''' in '''Perl''' | ||
|- | |- | ||
− | |00 | + | |00:43 |
|Knowledge of ''' Comments, loops''' and ''' conditional statements''' will be an added advantage. | |Knowledge of ''' Comments, loops''' and ''' conditional statements''' will be an added advantage. | ||
|- | |- | ||
− | |00 | + | |00:48 |
|Please go through the relevant spoken tutorials on the '''spoken tutorial''' website. | |Please go through the relevant spoken tutorials on the '''spoken tutorial''' website. | ||
|- | |- | ||
− | |00 | + | |00:54 |
|'''Perl''' provides certain inbuilt '''functions.''' | |'''Perl''' provides certain inbuilt '''functions.''' | ||
|- | |- | ||
− | |00 | + | |00:57 |
|These '''functions''' can perform various operations on an '''Array. ''' | |These '''functions''' can perform various operations on an '''Array. ''' | ||
|- | |- | ||
− | | 01 | + | | 01:02 |
| Let us first learn how to add and remove elements from last position of an '''Array'''. | | Let us first learn how to add and remove elements from last position of an '''Array'''. | ||
|- | |- | ||
− | |01 | + | |01:08 |
|'This can be done by using; | |'This can be done by using; | ||
|- | |- | ||
− | |01 | + | |01:10 |
| '''push function''' which adds an element at the last position of an '''Array''' | | '''push function''' which adds an element at the last position of an '''Array''' | ||
|- | |- | ||
− | |01 | + | |01:15 |
|and ''' pop function''' which removes an element from the last position of an '''Array''' | |and ''' pop function''' which removes an element from the last position of an '''Array''' | ||
|- | |- | ||
− | |01 | + | |01:21 |
| Let us understand '''push''' and '''pop functions''' by using a sample program. | | Let us understand '''push''' and '''pop functions''' by using a sample program. | ||
|- | |- | ||
− | |01 | + | |01:26 |
|Open the terminal and type ''' gedit perlArray dot pl space ampersand ''' | |Open the terminal and type ''' gedit perlArray dot pl space ampersand ''' | ||
|- | |- | ||
− | |01 | + | |01:33 |
| And Press ''' Enter ''' | | And Press ''' Enter ''' | ||
|- | |- | ||
− | | 01 | + | | 01:36 |
|This will open ''' perlArray dot pl''' file in '''gedit'''. | |This will open ''' perlArray dot pl''' file in '''gedit'''. | ||
|- | |- | ||
− | |01 | + | |01:41 |
|Type the code as shown on the screen | |Type the code as shown on the screen | ||
|- | |- | ||
− | |01 | + | |01:45 |
| Here, we have declared an '''Array''' of length 3. | | Here, we have declared an '''Array''' of length 3. | ||
|- | |- | ||
− | | 01 | + | | 01:50 |
| '''push function''' will insert an element at the last position of this '''Array''' i.e after 3; | | '''push function''' will insert an element at the last position of this '''Array''' i.e after 3; | ||
|- | |- | ||
− | |01 | + | |01:57 |
|whereas, ''' pop function''' will remove an element from the last position of the '''Array'''. | |whereas, ''' pop function''' will remove an element from the last position of the '''Array'''. | ||
|- | |- | ||
− | |02 | + | |02:04 |
|In our case, 4 will be removed from the '''Array'''. | |In our case, 4 will be removed from the '''Array'''. | ||
|- | |- | ||
− | |02 | + | |02:08 |
|Press '''Ctrl + S''' to save the file. | |Press '''Ctrl + S''' to save the file. | ||
|- | |- | ||
− | |02 | + | |02:11 |
|'''push function''' takes 2 '''arguments'''- | |'''push function''' takes 2 '''arguments'''- | ||
|- | |- | ||
− | |02 | + | |02:14 |
|'''1st argument''' to the '''push function''', is the '''Array''' in which to add an '''element'''. | |'''1st argument''' to the '''push function''', is the '''Array''' in which to add an '''element'''. | ||
|- | |- | ||
− | |02 | + | |02:20 |
|''' 2nd argument''' is the '''element''' which is to be '''pushed''' into the '''Array'''. | |''' 2nd argument''' is the '''element''' which is to be '''pushed''' into the '''Array'''. | ||
|- | |- | ||
− | |02 | + | |02:25 |
| The syntax of ''' pop function''' is as follows - | | The syntax of ''' pop function''' is as follows - | ||
|- | |- | ||
− | |02 | + | |02:29 |
|''' pop function''' takes only one '''argument ''' | |''' pop function''' takes only one '''argument ''' | ||
|- | |- | ||
− | |02 | + | |02:32 |
|It is the '''Array''' from which an '''element''' needs to be removed. | |It is the '''Array''' from which an '''element''' needs to be removed. | ||
|- | |- | ||
− | |02 | + | |02:36 |
|Note: Both these functions work at ''' last position''' of an '''Array'''. | |Note: Both these functions work at ''' last position''' of an '''Array'''. | ||
|- | |- | ||
− | |02 | + | |02:41 |
|The '''element''' removed by ''' pop function''' can be collected into another '''variable'''. | |The '''element''' removed by ''' pop function''' can be collected into another '''variable'''. | ||
|- | |- | ||
− | |02 | + | |02:46 |
|The syntax for this is ''' $variable space = space pop open bracket @myArray close bracket ''' | |The syntax for this is ''' $variable space = space pop open bracket @myArray close bracket ''' | ||
|- | |- | ||
− | |02 | + | |02:57 |
|Now switch to the terminal and execute the '''Perl script'''. | |Now switch to the terminal and execute the '''Perl script'''. | ||
|- | |- | ||
− | |03 | + | |03:01 |
|Type '''perl perlArray dot pl''' and press '''Enter.''' | |Type '''perl perlArray dot pl''' and press '''Enter.''' | ||
|- | |- | ||
− | | 03 | + | | 03:07 |
| The output is as shown on the terminal. | | The output is as shown on the terminal. | ||
|- | |- | ||
− | | 03 | + | | 03:11 |
| Now, let us see how to add/remove an '''element''' from the ''' 1st position''' of an ''' Array'''. | | Now, let us see how to add/remove an '''element''' from the ''' 1st position''' of an ''' Array'''. | ||
|- | |- | ||
− | | 03 | + | | 03:18 |
|This can be achieved using- | |This can be achieved using- | ||
|- | |- | ||
− | |03 | + | |03:20 |
|''' unshift function''' - which adds an '''element''' to an '''Array''' at the 1st position | |''' unshift function''' - which adds an '''element''' to an '''Array''' at the 1st position | ||
|- | |- | ||
− | |03 | + | |03:25 |
|''' shift function''' - which removes the first '''element''' from an '''Array'''. | |''' shift function''' - which removes the first '''element''' from an '''Array'''. | ||
|- | |- | ||
− | | 03 | + | | 03:31 |
|Let us understand this using a sample program. | |Let us understand this using a sample program. | ||
|- | |- | ||
− | |03 | + | |03:35 |
|I will open ''' perlArray dot pl''' file which I have already created. | |I will open ''' perlArray dot pl''' file which I have already created. | ||
|- | |- | ||
− | | 03 | + | | 03:39 |
| Type the following piece of code as shown on the screen. | | Type the following piece of code as shown on the screen. | ||
|- | |- | ||
− | | 03 | + | | 03:43 |
| ''' unshift''' function will insert an '''element''' at the first position i.e before 1 | | ''' unshift''' function will insert an '''element''' at the first position i.e before 1 | ||
|- | |- | ||
− | | 03 | + | | 03:52 |
| '''shift''' function will remove an ''' element''' from the first position. | | '''shift''' function will remove an ''' element''' from the first position. | ||
|- | |- | ||
− | | 03 | + | | 03:57 |
| In our case, ''' zero''' will be removed. | | In our case, ''' zero''' will be removed. | ||
|- | |- | ||
− | | 04 | + | | 04:00 |
| Press '''Ctrl + S''' to save the file. | | Press '''Ctrl + S''' to save the file. | ||
|- | |- | ||
− | |04 | + | |04:03 |
|The ''' unshift function''' takes 2 '''arguments '''- | |The ''' unshift function''' takes 2 '''arguments '''- | ||
|- | |- | ||
− | |04 | + | |04:06 |
|'''1st argument''' is the '''Array''' in which to add an '''element''' | |'''1st argument''' is the '''Array''' in which to add an '''element''' | ||
|- | |- | ||
− | |04 | + | |04:10 |
|''' 2nd argument''' is the '''element''' to be added into the '''Array ''' | |''' 2nd argument''' is the '''element''' to be added into the '''Array ''' | ||
|- | |- | ||
− | |04 | + | |04:15 |
|''' shift function''' takes only one '''argument''' - | |''' shift function''' takes only one '''argument''' - | ||
|- | |- | ||
− | |04 | + | |04:18 |
|This is the '''Array''' from which the '''element ''' needs to be removed. | |This is the '''Array''' from which the '''element ''' needs to be removed. | ||
|- | |- | ||
− | | 04 | + | | 04:22 |
| ''' Note:''' Both these functions works at '''first position''' of an '''Array'''. | | ''' Note:''' Both these functions works at '''first position''' of an '''Array'''. | ||
|- | |- | ||
− | | 04 | + | | 04:27 |
| We can collect the '''element''' removed by '''shift function''' into some variable. | | We can collect the '''element''' removed by '''shift function''' into some variable. | ||
|- | |- | ||
− | |04 | + | |04:33 |
|This syntax for this is ''' - $variable space = space shift open bracket @myArray close bracket ''' | |This syntax for this is ''' - $variable space = space shift open bracket @myArray close bracket ''' | ||
|- | |- | ||
− | |04 | + | |04:44 |
|Then switch to the terminal and execute the ''' Perl script'''. | |Then switch to the terminal and execute the ''' Perl script'''. | ||
|- | |- | ||
− | |04 | + | |04:48 |
|Type ''' perl perlArray dot pl''' and press '''Enter'''. | |Type ''' perl perlArray dot pl''' and press '''Enter'''. | ||
|- | |- | ||
− | |04 | + | |04:54 |
|The output displayed on the terminal is as highlighted. | |The output displayed on the terminal is as highlighted. | ||
|- | |- | ||
− | |04 | + | |04:59 |
|Now, let us see how to remove an ''' element''' from a specified position of an '''Array.''' | |Now, let us see how to remove an ''' element''' from a specified position of an '''Array.''' | ||
|- | |- | ||
− | |05 | + | |05:05 |
|''' splice function''' removes an ''' element''' from a specified position of an '''Array'''. | |''' splice function''' removes an ''' element''' from a specified position of an '''Array'''. | ||
|- | |- | ||
− | |05 | + | |05:11 |
|The ''' return value''' of this '''function''' is an ''' Array''' of removed elements. | |The ''' return value''' of this '''function''' is an ''' Array''' of removed elements. | ||
|- | |- | ||
− | |05 | + | |05:17 |
|Let us understand this using a sample program. | |Let us understand this using a sample program. | ||
|- | |- | ||
− | | 05 | + | | 05:21 |
|Go to the ''' perlArray dot pl ''' file, which we created earlier. | |Go to the ''' perlArray dot pl ''' file, which we created earlier. | ||
|- | |- | ||
− | | 05 | + | | 05:26 |
| Type the piece of code as shown on the screen. | | Type the piece of code as shown on the screen. | ||
|- | |- | ||
− | |05 | + | |05:30 |
| We need to provide ''' index''' from where we want to remove the ''' elements''' and | | We need to provide ''' index''' from where we want to remove the ''' elements''' and | ||
|- | |- | ||
− | | 05 | + | | 05:35 |
| the ''' offset''' upto which we want to remove the '''elements ''' | | the ''' offset''' upto which we want to remove the '''elements ''' | ||
|- | |- | ||
− | | 05 | + | | 05:39 |
| In our case, the '''elements''' 5 and 6 will be removed. | | In our case, the '''elements''' 5 and 6 will be removed. | ||
|- | |- | ||
− | | 05 | + | | 05:44 |
| Then switch to the ''' terminal''' and execute the ''' Perl script''' by typing - | | Then switch to the ''' terminal''' and execute the ''' Perl script''' by typing - | ||
|- | |- | ||
− | | 05 | + | | 05:49 |
| ''' perl perlArray dot pl''' and press '''Enter.''' | | ''' perl perlArray dot pl''' and press '''Enter.''' | ||
|- | |- | ||
− | |05 | + | |05:55 |
|The output is as shown on the terminal | |The output is as shown on the terminal | ||
|- | |- | ||
− | | 05 | + | | 05:59 |
| Now let us look at few other ''' inbuilt functions''' of '''Arrays.''' | | Now let us look at few other ''' inbuilt functions''' of '''Arrays.''' | ||
|- | |- | ||
− | | 06 | + | | 06:04 |
| ''' split function''' is used to divide a '''string''' at a specified '''delimiter. ''' | | ''' split function''' is used to divide a '''string''' at a specified '''delimiter. ''' | ||
|- | |- | ||
− | |06 | + | |06:10 |
|The return value of this ''' function''' is an '''Array'''. | |The return value of this ''' function''' is an '''Array'''. | ||
|- | |- | ||
− | | 06 | + | | 06:14 |
|The ''' elements''' of this '''Array''' are the divided portions of the '''string.''' | |The ''' elements''' of this '''Array''' are the divided portions of the '''string.''' | ||
|- | |- | ||
− | |06 | + | |06:19 |
| ''' join function''' joins the '''elements''' of an '''Array''' , using the specified '''delimiter. ''' | | ''' join function''' joins the '''elements''' of an '''Array''' , using the specified '''delimiter. ''' | ||
|- | |- | ||
− | |06 | + | |06:25 |
|It returns a string of joined '''elements.''' | |It returns a string of joined '''elements.''' | ||
|- | |- | ||
− | | 06 | + | | 06:28 |
| ''' sort function''' sorts an '''Array''' in alphabetical/numerical order. | | ''' sort function''' sorts an '''Array''' in alphabetical/numerical order. | ||
|- | |- | ||
− | | 06 | + | | 06:34 |
| ''' qw function ''' returns an '''Array''' of words, separated by a '''white space'''. | | ''' qw function ''' returns an '''Array''' of words, separated by a '''white space'''. | ||
|- | |- | ||
− | | 06 | + | | 06:40 |
| Now let us understand all these ''' functions''' using a sample program. | | Now let us understand all these ''' functions''' using a sample program. | ||
|- | |- | ||
− | | 06 | + | | 06:45 |
|Switch to ''' terminal''' and type | |Switch to ''' terminal''' and type | ||
|- | |- | ||
− | |06 | + | |06:48 |
| ''' gedit arrayFunctions dot pl space ampersand and Press Enter''' | | ''' gedit arrayFunctions dot pl space ampersand and Press Enter''' | ||
|- | |- | ||
− | |06 | + | |06:55 |
|Type the following piece of code as shown on screen. | |Type the following piece of code as shown on screen. | ||
|- | |- | ||
− | |07 | + | |07:00 |
|In this case, each word of the ''' variable string''' will become an ''' element''' of an '''Array''' | |In this case, each word of the ''' variable string''' will become an ''' element''' of an '''Array''' | ||
|- | |- | ||
− | |07 | + | |07:07 |
| Here, each '''element''' of '''newArray''' will be joined by '''comma'''. | | Here, each '''element''' of '''newArray''' will be joined by '''comma'''. | ||
|- | |- | ||
− | |07 | + | |07:12 |
|''' sort function''' will sort the '''elements''' of an '''Array''' in alphabetical order. | |''' sort function''' will sort the '''elements''' of an '''Array''' in alphabetical order. | ||
|- | |- | ||
− | |07 | + | |07:19 |
| '''qw function''' creates an '''Array''' of words separated by space. | | '''qw function''' creates an '''Array''' of words separated by space. | ||
|- | |- | ||
− | |07 | + | |07:25 |
| Let us understand each '''function.''' | | Let us understand each '''function.''' | ||
|- | |- | ||
− | |07 | + | |07:28 |
|'''split function''' takes two '''arguments'''. | |'''split function''' takes two '''arguments'''. | ||
|- | |- | ||
− | |07 | + | |07:31 |
|''' 1st argument''' is the ''' delimiter''' by which the ''' string''' needs to be split | |''' 1st argument''' is the ''' delimiter''' by which the ''' string''' needs to be split | ||
|- | |- | ||
− | |07 | + | |07:36 |
|''' 2nd''' is the '''string''' which needs to be split. | |''' 2nd''' is the '''string''' which needs to be split. | ||
|- | |- | ||
− | |07 | + | |07:39 |
|'''Delimiters''' can be specified in ''' forward slash, single or double quotes. ''' | |'''Delimiters''' can be specified in ''' forward slash, single or double quotes. ''' | ||
|- | |- | ||
− | |07 | + | |07:45 |
|''' join function''' takes 2 '''arguments'''. | |''' join function''' takes 2 '''arguments'''. | ||
|- | |- | ||
− | |07 | + | |07:48 |
|1st is the '''delimiter''' by which the '''Array elements''' needs to be joined. | |1st is the '''delimiter''' by which the '''Array elements''' needs to be joined. | ||
|- | |- | ||
− | |07 | + | |07:53 |
|2nd is the '''Array.''' | |2nd is the '''Array.''' | ||
|- | |- | ||
− | |07 | + | |07:55 |
|'''Delimiters''' can be specified in '''single or double quotes. ''' | |'''Delimiters''' can be specified in '''single or double quotes. ''' | ||
|- | |- | ||
− | |07 | + | |07:58 |
| ''' sort function''' takes a single '''argument''' , which is the '''Array''' that needs to be sorted. | | ''' sort function''' takes a single '''argument''' , which is the '''Array''' that needs to be sorted. | ||
|- | |- | ||
− | |08 | + | |08:05 |
|''' qw function''' returns an ''' Array''' of words, separated by ''' space.''' | |''' qw function''' returns an ''' Array''' of words, separated by ''' space.''' | ||
|- | |- | ||
− | |08 | + | |08:11 |
|It is not necessary to specify the word in ''' quotes''' , if written using '''qw. ''' | |It is not necessary to specify the word in ''' quotes''' , if written using '''qw. ''' | ||
|- | |- | ||
− | |08 | + | |08:17 |
|Then switch to the terminal and execute the ''' Perl script''' by typing - | |Then switch to the terminal and execute the ''' Perl script''' by typing - | ||
|- | |- | ||
− | |08 | + | |08:23 |
|''' perl arrayFunctions dot pl''' | |''' perl arrayFunctions dot pl''' | ||
|- | |- | ||
− | |08 | + | |08:26 |
|and press '''Enter.''' | |and press '''Enter.''' | ||
|- | |- | ||
− | |08 | + | |08:29 |
|The following output is displayed on the screen. | |The following output is displayed on the screen. | ||
|- | |- | ||
− | |08 | + | |08:33 |
|Let us summarize. | |Let us summarize. | ||
|- | |- | ||
− | |08 | + | |08:34 |
|In this tutorial, we have learnt to - | |In this tutorial, we have learnt to - | ||
|- | |- | ||
− | |08 | + | |08:36 |
|add/remove ''' elements''' from an '''Array ''' | |add/remove ''' elements''' from an '''Array ''' | ||
|- | |- | ||
− | |08 | + | |08:40 |
|basic functions which can be performed on '''Array''' using sample programs | |basic functions which can be performed on '''Array''' using sample programs | ||
|- | |- | ||
− | |08 | + | |08:46 |
|Here is assignment for you - | |Here is assignment for you - | ||
|- | |- | ||
− | |08 | + | |08:48 |
|'script.spoken-tutorial.org/index.php/Perl' | |'script.spoken-tutorial.org/index.php/Perl' | ||
|- | |- | ||
− | |08 | + | |08:54 |
|split the above ''' string at '/ ' ''' (forward slash) '''delimiter ''' | |split the above ''' string at '/ ' ''' (forward slash) '''delimiter ''' | ||
|- | |- | ||
− | |08 | + | |08:59 |
|Add ''' https:// ''' at the start of an newly created '''Array''' | |Add ''' https:// ''' at the start of an newly created '''Array''' | ||
|- | |- | ||
− | |09 | + | |09:06 |
|Remove ''' element “Perl” ''' from the '''Array ''' | |Remove ''' element “Perl” ''' from the '''Array ''' | ||
|- | |- | ||
− | |09 | + | |09:09 |
|Declare number '''Array ''' and sort it | |Declare number '''Array ''' and sort it | ||
|- | |- | ||
− | |09 | + | |09:12 |
|Watch the video available at the following link | |Watch the video available at the following link | ||
|- | |- | ||
− | |09 | + | |09:15 |
|It summaries the Spoken Tutorial project | |It summaries the Spoken Tutorial project | ||
|- | |- | ||
− | |09 | + | |09:19 |
|If you do not have good bandwidth, you can download and watch it | |If you do not have good bandwidth, you can download and watch it | ||
|- | |- | ||
− | | 09 | + | | 09:24 |
| The Spoken Tutorial Project Team Conducts workshops using spoken tutorials | | The Spoken Tutorial Project Team Conducts workshops using spoken tutorials | ||
|- | |- | ||
− | |09 | + | |09:30 |
|Gives certificates to those who pass an online test | |Gives certificates to those who pass an online test | ||
|- | |- | ||
− | |09 | + | |09:34 |
|For more details, please write to contact at spoken hyphen tutorial dot org | |For more details, please write to contact at spoken hyphen tutorial dot org | ||
|- | |- | ||
− | | 09 | + | | 09:40 |
| Spoken Tutorial Project is a part of the Talk to a Teacher project | | Spoken Tutorial Project is a part of the Talk to a Teacher project | ||
|- | |- | ||
− | |09 | + | |09:44 |
|It is supported by the National Mission on Education through ICT, MHRD, Government of India. | |It is supported by the National Mission on Education through ICT, MHRD, Government of India. | ||
|- | |- | ||
− | |09 | + | |09:51 |
|More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro | |More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro | ||
|- | |- | ||
− | | 10 | + | | 10:02 |
| Hope you enjoyed this Perl tutorial. | | Hope you enjoyed this Perl tutorial. | ||
|- | |- | ||
− | |10 | + | |10:04 |
|This is Amol signing off. | |This is Amol signing off. | ||
|- | |- | ||
− | |10 | + | |10:06 |
|Thanks for joining. | |Thanks for joining. | ||
|} | |} |
Revision as of 11:27, 10 July 2014
Time | Narration |
00:01 | Welcome to the spoken tutorial on Array Functions in Perl |
00:06 | In this tutorial, we will learn about Array functions in Perl, like |
00:11 | push |
00:11 | pop |
00:12 | shift |
00:14 | unshift |
00:15 | split |
00:16 | splice |
00:17 | and join |
00:18 | sort |
00:19 | qw |
00:20 | I am using Ubuntu Linux12.04 operating system and Perl 5.14.2 |
00:28 | I will also be using the gedit Text Editor. |
00:32 | You can use any text editor of your choice. |
00:36 | You should have basic knowledge of Variables, Data Structures and Arrays in Perl |
00:43 | Knowledge of Comments, loops and conditional statements will be an added advantage. |
00:48 | Please go through the relevant spoken tutorials on the spoken tutorial website. |
00:54 | Perl provides certain inbuilt functions. |
00:57 | These functions can perform various operations on an Array. |
01:02 | Let us first learn how to add and remove elements from last position of an Array. |
01:08 | 'This can be done by using; |
01:10 | push function which adds an element at the last position of an Array |
01:15 | and pop function which removes an element from the last position of an Array |
01:21 | Let us understand push and pop functions by using a sample program. |
01:26 | Open the terminal and type gedit perlArray dot pl space ampersand |
01:33 | And Press Enter |
01:36 | This will open perlArray dot pl file in gedit. |
01:41 | Type the code as shown on the screen |
01:45 | Here, we have declared an Array of length 3. |
01:50 | push function will insert an element at the last position of this Array i.e after 3; |
01:57 | whereas, pop function will remove an element from the last position of the Array. |
02:04 | In our case, 4 will be removed from the Array. |
02:08 | Press Ctrl + S to save the file. |
02:11 | push function takes 2 arguments- |
02:14 | 1st argument to the push function, is the Array in which to add an element. |
02:20 | 2nd argument is the element which is to be pushed into the Array. |
02:25 | The syntax of pop function is as follows - |
02:29 | pop function takes only one argument |
02:32 | It is the Array from which an element needs to be removed. |
02:36 | Note: Both these functions work at last position of an Array. |
02:41 | The element removed by pop function can be collected into another variable. |
02:46 | The syntax for this is $variable space = space pop open bracket @myArray close bracket |
02:57 | Now switch to the terminal and execute the Perl script. |
03:01 | Type perl perlArray dot pl and press Enter. |
03:07 | The output is as shown on the terminal. |
03:11 | Now, let us see how to add/remove an element from the 1st position of an Array. |
03:18 | This can be achieved using- |
03:20 | unshift function - which adds an element to an Array at the 1st position |
03:25 | shift function - which removes the first element from an Array. |
03:31 | Let us understand this using a sample program. |
03:35 | I will open perlArray dot pl file which I have already created. |
03:39 | Type the following piece of code as shown on the screen. |
03:43 | unshift function will insert an element at the first position i.e before 1 |
03:52 | shift function will remove an element from the first position. |
03:57 | In our case, zero will be removed. |
04:00 | Press Ctrl + S to save the file. |
04:03 | The unshift function takes 2 arguments - |
04:06 | 1st argument is the Array in which to add an element |
04:10 | 2nd argument is the element to be added into the Array |
04:15 | shift function takes only one argument - |
04:18 | This is the Array from which the element needs to be removed. |
04:22 | Note: Both these functions works at first position of an Array. |
04:27 | We can collect the element removed by shift function into some variable. |
04:33 | This syntax for this is - $variable space = space shift open bracket @myArray close bracket |
04:44 | Then switch to the terminal and execute the Perl script. |
04:48 | Type perl perlArray dot pl and press Enter. |
04:54 | The output displayed on the terminal is as highlighted. |
04:59 | Now, let us see how to remove an element from a specified position of an Array. |
05:05 | splice function removes an element from a specified position of an Array. |
05:11 | The return value of this function is an Array of removed elements. |
05:17 | Let us understand this using a sample program. |
05:21 | Go to the perlArray dot pl file, which we created earlier. |
05:26 | Type the piece of code as shown on the screen. |
05:30 | We need to provide index from where we want to remove the elements and |
05:35 | the offset upto which we want to remove the elements |
05:39 | In our case, the elements 5 and 6 will be removed. |
05:44 | Then switch to the terminal and execute the Perl script by typing - |
05:49 | perl perlArray dot pl and press Enter. |
05:55 | The output is as shown on the terminal |
05:59 | Now let us look at few other inbuilt functions of Arrays. |
06:04 | split function is used to divide a string at a specified delimiter. |
06:10 | The return value of this function is an Array. |
06:14 | The elements of this Array are the divided portions of the string. |
06:19 | join function joins the elements of an Array , using the specified delimiter. |
06:25 | It returns a string of joined elements. |
06:28 | sort function sorts an Array in alphabetical/numerical order. |
06:34 | qw function returns an Array of words, separated by a white space. |
06:40 | Now let us understand all these functions using a sample program. |
06:45 | Switch to terminal and type |
06:48 | gedit arrayFunctions dot pl space ampersand and Press Enter |
06:55 | Type the following piece of code as shown on screen. |
07:00 | In this case, each word of the variable string will become an element of an Array |
07:07 | Here, each element of newArray will be joined by comma. |
07:12 | sort function will sort the elements of an Array in alphabetical order. |
07:19 | qw function creates an Array of words separated by space. |
07:25 | Let us understand each function. |
07:28 | split function takes two arguments. |
07:31 | 1st argument is the delimiter by which the string needs to be split |
07:36 | 2nd is the string which needs to be split. |
07:39 | Delimiters can be specified in forward slash, single or double quotes. |
07:45 | join function takes 2 arguments. |
07:48 | 1st is the delimiter by which the Array elements needs to be joined. |
07:53 | 2nd is the Array. |
07:55 | Delimiters can be specified in single or double quotes. |
07:58 | sort function takes a single argument , which is the Array that needs to be sorted. |
08:05 | qw function returns an Array of words, separated by space. |
08:11 | It is not necessary to specify the word in quotes , if written using qw. |
08:17 | Then switch to the terminal and execute the Perl script by typing - |
08:23 | perl arrayFunctions dot pl |
08:26 | and press Enter. |
08:29 | The following output is displayed on the screen. |
08:33 | Let us summarize. |
08:34 | In this tutorial, we have learnt to - |
08:36 | add/remove elements from an Array |
08:40 | basic functions which can be performed on Array using sample programs |
08:46 | Here is assignment for you - |
08:48 | 'script.spoken-tutorial.org/index.php/Perl' |
08:54 | split the above string at '/ ' (forward slash) delimiter |
08:59 | Add https:// at the start of an newly created Array |
09:06 | Remove element “Perl” from the Array |
09:09 | Declare number Array and sort it |
09:12 | Watch the video available at the following link |
09:15 | It summaries the Spoken Tutorial project |
09:19 | If you do not have good bandwidth, you can download and watch it |
09:24 | The Spoken Tutorial Project Team Conducts workshops using spoken tutorials |
09:30 | Gives certificates to those who pass an online test |
09:34 | For more details, please write to contact at spoken hyphen tutorial dot org |
09:40 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
09:44 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
09:51 | More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro |
10:02 | Hope you enjoyed this Perl tutorial. |
10:04 | This is Amol signing off. |
10:06 | Thanks for joining. |