Difference between revisions of "PERL/C3/Sample-PERL-program/English-timed"

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|00:01
 
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|Welcome to the''' Spoken Tutorial''' on''' Sample PERL program.'''
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|Welcome to the '''Spoken Tutorial''' on '''Sample PERL program.'''
  
 
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|To record this tutorial, I am using:
 
|To record this tutorial, I am using:
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* '''Ubuntu Linux 12.04''' operating system
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'''Ubuntu Linux 12.04''' operating system
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* '''Perl 5.14.2''' and the
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'''Perl 5.14.2''' and the
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* '''gedit''' Text Editor.
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'''gedit''' Text editor.
  
 
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|00:39
 
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|The sample Perl program will give the output of various weather forecast reports of a region.
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|The sample '''Perl''' program will give the '''output''' of various weather forecast reports of a region.
  
 
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|'''Weather dot pm''' is a''' module''' file that has a complex data-structure to hold the data required for this program.
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|'''weather dot pm''' is a''' module''' file that has a complex '''data-structure''' to hold the data required for this program.
  
 
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|'''Weather underscore report dot pl''' is the''' Perl''' program which makes use of this '''module '''file to give the required output.
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|'''weather underscore report dot pl''' is the''' Perl''' program which makes use of this '''module '''file to give the required output.
  
 
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|Download and unzip the files provided in the code file link.
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|Download and '''unzip''' the files provided in the '''code file link'''.
  
 
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|Here, I have used''' references''' to create complex data-structures to hold the data required for a weather report.
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|Here, I have used''' references''' to create complex data-structures, to hold the data required for a weather-report.
  
 
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|*Each week day has four '''keys''' -  
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|Each week day has four '''keys''' -  
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'''max underscore temp'''  
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  '''max underscore temp''',
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'''min underscore temp'''  
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  '''min underscore temp''',
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'''sunrise'''
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  '''sunrise''',
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'''sunset.'''
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  '''sunset.'''
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| The 'week day'- passed as parameter from the main program, is assigned to a local variable '''dollar week underscore day'''.
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| The week-day, passed as parameter from the '''main''' program, is assigned to a local variable '''dollar week underscore day'''.
  
 
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|The '''print statements''' will print the corresponding data of a specified week day to a file.
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|The print statements will print the corresponding data of a specified week day, to a file.
  
 
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|Now, let us see - a '''Perl '''program '''weather underscore report dot pl ''' where we will make use of this '''module '''file '''Weather dot pm'''.
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|Now, let us see a '''Perl '''program, '''weather underscore report dot pl ''' where we will make use of this '''module '''file '''Weather dot pm'''.
  
 
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|The user has to enter an option to print:
 
|The user has to enter an option to print:
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* the  daily weather report of a particular week day  
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the  daily weather report of a particular week day  
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* daily weather report of a particular week day to an output file
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daily weather report of a particular week day to an output file
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* weekly weather report.
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weekly weather report.
  
 
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|Next, we can see that we are calling two functions-
 
|Next, we can see that we are calling two functions-
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*''' display_header()''' and
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''' display_header()''' and
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*''' display_daily_report().'''
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''' display_daily_report().'''
  
 
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|Here, the exit value of '0' indicates the program ran successfully.
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|Here, the exit value of '0', indicates the program ran successfully.
  
 
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|Now I'll again execute the program once again to demonstrate the other options.
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|Now, I'll execute the program once again to demonstrate the other options.
  
 
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|At the prompt, we have to type any week day. I will type "wednesday" and press '''Enter'''.
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|At the prompt, we have to type any week day. I will type "Wednesday" and press '''Enter'''.
  
 
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|We can see a message: '''Please check the file wednesday dot txt for report output '''.
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|We can see a message: "Please check the file wednesday dot txt for report output".
  
 
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|The output file has been created with the entered week day name with 'txt' extension.
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|The output file has been created with the entered week day name, with 'txt' extension.
  
 
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|Switch to the terminal and type:''' perl weather underscore report dot pl '''and press''' Enter'''.
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|Switch to the '''terminal''' and type:''' perl weather underscore report dot pl '''and press''' Enter'''.
  
 
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|Type '3 'and press '''Enter.'''
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|Type '3' and press '''Enter.'''
  
 
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| Write the required functions in the module '''Employee dot pm '''file.
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| Write the required functions in the '''module''' '''Employee dot pm '''file.
  
 
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|10:56
 
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| The video at the following link summarize the '''spoken tutorial'''. Please download and watch it.
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| The video at the following '''link''' summarizes the '''spoken tutorial'''. Please download and watch it.
  
 
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|11:03
 
|11:03
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| We conduct workshops and give certificates for those who pass our online tests.
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| We conduct workshops and give certificates for those who pass our online tests.For more details, please write to us.
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+
−
For more details, please write to us.
+
  
 
|-
 
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|11:12
 
|11:12
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|Spoken Tutorial project is funded by NMEICT, MHRD, Government of India.
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|Spoken Tutorial project is funded by NMEICT, MHRD, Government of India.More information on this mission is available at this '''link'''.
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More information on this mission is available at this link.
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Latest revision as of 18:24, 20 February 2017

Time
Narration
00:01 Welcome to the Spoken Tutorial on Sample PERL program.
00:06 In this tutorial, we will learn to include all the major topics we covered so far

in a sample Perl program.

00:14 To record this tutorial, I am using:

Ubuntu Linux 12.04 operating system Perl 5.14.2 and the gedit Text editor.

00:25 You can use any text editor of your choice.
00:29 As a prerequisite, you should have working knowledge of Perl programming.
00:34 If not, then go through the relevant Perl spoken tutorials on this website.
00:39 The sample Perl program will give the output of various weather forecast reports of a region.
00:46 weather dot pm is a module file that has a complex data-structure to hold the data required for this program.
00:54 It also contains various functions to generate the report.
00:59 weather underscore report dot pl is the Perl program which makes use of this module file to give the required output.
01:08 The same code files are available under this video on our website.
01:13 Download and unzip the files provided in the code file link.
01:18 Now, let us see our sample Perl program Weather dot pm.
01:24 The block of code in this program is under the namespace Weather.
01:29 Perl implements namespace using the package keyword.
01:34 BEGIN block is compiled and executed before the main program.
01:40 Export allows to export the functions and variables of modules to user's namespace.
01:48 At the rate EXPORT and at the rate EXPORT underscore OK are the two main variables used during export operation.
01:57 At the rate EXPORT contains list of subroutines and variables of the module.
02:03 These will be exported into the caller namespace.
02:07 At the rate EXPORT underscore OK does export of symbols on demand basis.
02:14 Here, I have used references to create complex data-structures, to hold the data required for a weather-report.
02:24 $weather_report is a hash reference. “place” and “nstate” have the scalar values.
02:32 “weekly” is hash of hash references.
02:37 Each week day has four keys -

max underscore temp min underscore temp sunrise sunset.

02:48 “record underscore time” is an array reference with two index values.
02:54 I have a few subroutines to display the weather report of various options.

Let us see one by one.

03:01 This function prints the header information such as header of the report, place, state and current date.
03:10 Now, let us see the next function display underscore daily underscore report.
03:16 This function prints the daily report on the screen, depending upon the weekday input.
03:22 We retrieve the parameter passed into a subroutine using the shift function.
03:27 I have used the trim() function to remove the leading and trailing spaces of the parameter value.
03:34 Here is the code for the trim() function.
03:37 Lc() function returns a lowercase version of the given input.
03:42 This is used to avoid case-sensitivity.
03:45 The week-day, passed as parameter from the main program, is assigned to a local variable dollar week underscore day.
03:55 The following print statements will print the data corresponding to a specified week day.
04:01 We are using the arrow operator to dereference a value in $weather underscore report.
04:09 When working with references, we have to understand the data type we are dereferencing.
04:15 If it is a hash, we need to pass the key in curly braces.
04:20 If it is an array, we need to use the square brackets with the index values.
04:26 return function of Perl returns a value.
04:29 This can be used to check the status of the function in the main program.
04:36 The next function is write underscore daily underscore report.
04:40 This function will print the report output to a file.
04:45 The open function with the greater than (>) symbol defines the WRITE mode.
04:50 Filename is created with the weekday name and dot txt extension.
04:56 The print statements will print the corresponding data of a specified week day, to a file.
05:02 This prints the weekly report.
05:05 I have declared a foreach loop to loop through each weekday of the hash reference.
05:11 I have used curly brackets to represent the hash reference and the arrow operator to dereference.
05:18 I am using the “keys” in-built function to loop through the keys of the hash.
05:23 display underscore daily underscore report function will print each element of the hash.
05:30 Now, let us see a Perl program, weather underscore report dot pl where we will make use of this module file Weather dot pm.
05:40 Here, use strict and use warnings are compiler flags that help to avoid common programming mistakes.
05:48 use Weather semicolon. Here, Weather is a module name which I have used in this program.
05:56 We have already seen that the functions required for this program have been stored in this module.
06:03 It is not required to give the dot pm file extension here.
06:08 In this program, I'll print different reports depending upon the given options.
06:14 The user has to enter an option to print:

the daily weather report of a particular week day daily weather report of a particular week day to an output file weekly weather report.

06:27 If option '1' is typed, it will ask the user to enter the day of a week.
06:32 The diamond operator will read from STDIN, that is, from the keyboard.
06:38 For example, if the user enters 'monday', then it is assigned to a variable dollar dayoption, which is a local variable.
06:47 Next, we can see that we are calling two functions-

display_header() and display_daily_report().

06:56 We have exported all functions in Weather dot pm with “use Weather” statement in this file.
07:03 So, no need to refer the functions within a package using the colon colon (::)package qualifier
07:10 Now let's see the next option.
07:13 If option '2' is typed, it will prompt the user to enter the day of a week.
07:19 $dayoption is passed as the input parameter to the function write underscore daily underscore report.
07:27 return value from the function is stored in the variable dollar result.
07:33 Print statement asks the user to check the text file for the output.
07:38 The filename is created with the day of the week dot txt as output file.
07:46 If option '3' is typed, it prints the weather report for the whole week.
07:51 display underscore weekly underscore report is the function name of the weekly report.
07:57 This print statement draws a horizontal line for the specified number of times.
08:02 This is just to give a good look to the report.
08:06 Lastly, if the option is 4, it will quit the program.
08:11 If any option other than the ones specified is given, the print statement says “Incorrect option”.
08:19 Here, the exit value of '0', indicates the program ran successfully.
08:25 The exit value other than '0' means an error of some kind has occurred.
08:31 Now, let us execute the program.
08:34 Switch to the terminal and type perl weather underscore report dot pl and press Enter.
08:41 We can see four options on the screen.
08:45 Type '1 'and press Enter.
08:48 We are prompted to enter a day of the week. I'll type "monday" and press Enter.
08:56 This is the header output generated from the function display underscore header().
09:02 Now, we can see the weather report of Monday.
09:06 Now, I'll execute the program once again to demonstrate the other options.
09:13 Type 2 and press Enter.
09:17 At the prompt, we have to type any week day. I will type "Wednesday" and press Enter.
09:25 We can see a message: "Please check the file wednesday dot txt for report output".
09:32 The output has been written to this text file. Let us open the file and check the contents.
09:38 Type: gedit wednesday dot txt and press Enter.
09:44 The output file has been created with the entered week day name, with 'txt' extension.
09:51 Now, let us check the next option.
09:54 Switch to the terminal and type: perl weather underscore report dot pl and press Enter.
10:00 Type '3' and press Enter.
10:04 This time, we can see the weekly weather report.
10:08 The hash keys and hash values are stored in a random order.
10:13 So, the displayed output is not related to the order in which they were added.
10:19 With this, we come to the end of this tutorial. Let us summarize.
10:24 In this tutorial, we have seen a sample Perl program by covering main topics of our previous tutorials.
10:32 As an assignment, write a similar Perl program employee underscore report.pl for displaying employee salary, designation, department, leave_balance details.
10:45 Pass Employee ID or Employee name as input.
10:50 Write the required functions in the module Employee dot pm file.
10:56 The video at the following link summarizes the spoken tutorial. Please download and watch it.
11:03 We conduct workshops and give certificates for those who pass our online tests.For more details, please write to us.
11:12 Spoken Tutorial project is funded by NMEICT, MHRD, Government of India.More information on this mission is available at this link.
11:25 This is Nirmala Venkat from IIT Bombay, signing off. Thanks for watching.

Contributors and Content Editors

PoojaMoolya, Sandhya.np14

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