Difference between revisions of "PERL/C2/Data-Structures/English-timed"
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Revision as of 11:27, 13 June 2014
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| 00.00 | Welcome to the spoken tutorial on Data Structures in Perl |
| 00.05 | In this tutorial, we will learn about Data Structures available in Perl |
| 00.11 | Here I am using Ubuntu Linux12.04 operating system and Perl 5.14.2 |
| 00.18 | I will also be using the gedit Text Editor. |
| 00.22 | You can use any text editor of your choice. |
| 00.25 | You should have basic knowledge of Variables in Perl |
| 00.29 | Knowledge of comments, loops and conditional statements will be an added advantage. |
| 00.36 | Please go through the relevant spoken tutorials on the spoken tutorial website. |
| 00.41 | Perl has 3 types of data structure - |
| 00.44 | Scalar |
| 00.45 | Array |
| 00.46 | Hash , also, called as Associative Array |
| 00.50 | Scalar: This type of data structure holds a value of any data type. |
| 00.56 | The data type can be string, number, double etc. |
| 01.01 | It can also hold the reference to an array or reference to a hash. |
| 01.06 | Note: Reference in Perl will be covered in subsequent tutorial. |
| 01.11 | Scalar type of data structure is as simple as declaring the variable. |
| 01.16 | $count = 12 semicolon |
| 01.20 | $string = in single quote 'I am scalar of type string' semicolon. |
| 01.26 | We can perform the following operations on scalar |
| 01.30 | Assign a value to it |
| 01.32 | Assign one scalar to another |
| 01.35 | Arithmetic operations on number type of scalars like add, subtract etc |
| 01.41 | string operations on string scalar like concatenation, substr etc |
| 01.48 | Now let us look at an example of scalar data structure. |
| 01.52 | Switch to terminal and type gedit scalars dot pl space & and press Enter. |
| 02.01 | This will open the scalars dot pl file in gedit. |
| 02.05 | Type the following code as displayed on the screen. |
| 02.09 | This is the declaration and assignment to the scalar. |
| 02.13 | These are few arithmetic operations that can be performed on number type of scalar |
| 02.19 | These are string operations that can be performed on string type of scalar. |
| 02.25 | substr is the PERL function which provides part of the string as output. |
| 02.30 | Here index 0 specifies start of a string, i.e. from where we want to start extraction of the string.
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| 02.39 | And 11 specify the offset upto where we want the string to be in the output. |
| 02.46 | Press ctrl + s to save the file. |
| 02.50 | Then switch to the terminal and execute the Perl script as |
| 02.55 | perl scalars dot pl and press Enter |
| 03.00 | The output shown on terminal is as highlighted |
| 03.05 | Now, let us look at array data structure in PERL. |
| 03.09 | Array: It is a list of elements. |
| 03.12 | Elements can be string, number etc. |
| 03.16 | It has an index, which is used for performing various operations on the array. |
| 03.22 | Index starts with zero. |
| 03.25 | Unlike other programming languages, there is no need to declare an array or its length before using it in Perl. |
| 03.33 | Perl array, stretches or shrinks as per the elements added or removed from it |
| 03.39 | The syntax to write an array is; |
| 03.41 | at the rate variableName space equal to space open bracket list of elements separated with comma close bracket semicolon |
| 03.54 | Now let us look at an example of array data structure. |
| 03.57 | Switch to terminal and type gedit perlArray dot pl space & and press Enter. |
| 04.08 | This will open the perlArray dot pl file in gedit. |
| 04.12 | Type the following code as displayed on the screen. |
| 04.18 | This is the number array which has elements of number type. |
| 04.23 | This is the string array which has elements of string type. |
| 04.29 | This array has elements of both number and string type. |
| 04.34 | This example shows the various types of arrays in Perl. |
| 04.39 | This is how we can print the array in Perl. |
| 04.43 | Press Ctrl + S to save the file. |
| 04.47 | Then switch to terminal and execute the Perl script as |
| 04.52 | perl perlArray dot pl and press Enter. |
| 04.59 | The following output is displayed on the terminal |
| 05.04 | Now, let us look at Hash data structure in Perl. |
| 05.08 | Hash is alternatively called as Associative array |
| 05.12 | It is a Key Value pair data structure. |
| 05.15 | Key in hash is unique. |
| 05.18 | If the same key is added again, then the value of that key will be overridden by the latest value assigned to the key. |
| 05.28 | Value can be duplicate. |
| 05.30 | It also holds value of any data type. |
| 05.34 | The syntax of hash is; |
| 05.36 | percentage variable name space equal to space open bracket |
| 05.41 | Press Enter |
| 05.42 | single quote key Name single quote space equal to greater than sign space Value comma |
| 05.50 | Press Enter |
| 05.52 | single quote key Name single quote space equal to greater than sign space Value |
| 05.58 | Press Enter |
| 06.00 | close bracket semicolon |
| 06.03 | Now let us look at an example of hash data structure. |
| 06.07 | Switch to terminal and type |
| 06.10 | gedit perlHash dot pl space & and press Enter. |
| 06.18 | This will open the perlHash dot pl file in gedit. |
| 06.22 | Type the following code as displayed on the screen. |
| 06.27 | This hash indicates the marks obtained in a subject. |
| 06.31 | This example, shows the use of hash |
| 06.35 | Now let us see how to print the hash |
| 06.38 | For now, just note the way I have printed the hash. |
| 06.42 | Detailed explanation will be given in subsequent tutorial. |
| 06.47 | Press Ctrl + S to save the file. |
| 06.50 | Then switch to terminal and execute the Perl script as |
| 06.55 | perl perlHash dot pl and press Enter. |
| 07.01 | The following output is displayed on the terminal |
| 07.05 | Let us summarize. |
| 07.06 | In this tutorial, we have learnt - |
| 07.09 | scalar |
| 07.10 | Array and |
| 07.11 | Hash Data Structure in Perl |
| 07.13 | using sample programs. |
| 07.15 | There is assignment for you - |
| 07.17 | Declare scalar variable |
| 07.19 | Assign value of type float to it and then print it. |
| 07.23 | Declare and print an array of colors 'Red', 'Yellow' and 'Green'. |
| 07.28 | Declare and print a hash of Employee Name and their department. |
| 07.33 | Hint: 'Employee' =>(equal to greater than sign) 'John' comma |
| 07.38 | 'Department' =>(equal to greater than sign) 'Engineering' |
| 07.42 | Watch the video available at the following link |
| 07.46 | It summaries the Spoken Tutorial project |
| 07.49 | If you do not have good bandwidth, you can download and watch it |
| 07.53 | The Spoken Tutorial Project Team Conducts workshops using spoken tutorials |
| 07.59 | Gives certificates to those who pass an online test |
| 08.03 | For more details, please write to contact at spoken hyphen tutorial dot org |
| 08.10 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
| 08.15 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
| 08.22 | More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro |
| 08.33 | Hope you enjoyed this Perl tutorial. |
| 08.35 | This is Amol signing off. |
| 08.38 | Thanks for joining. |
