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Analysing text files with Perl

P: 3
Analysing text files to obtain statistics on their content

You are to write a Perl program that analyses text files to obtain statistics on their content. The program should operate as follows:

1) When run, the program should check if an argument has been provided. If not, the program should prompt for, and accept input of, a filename from the keyboard.

2) The filename, either passed as an argument or input from the keyboard, should be checked to ensure it is in MS-DOS format. The filename part should be no longer than 8 characters and must begin with a letter or underscore character followed by up to 7 letters, digits or underscore characters. The file extension should be optional, but if given is should be ".TXT" (upper- or lowercase).

If no extension if given, ".TXT" should be added to the end of the filename. So, for example, if "testfile" is input as the filename, this should become "testfile.TXT". If "input.txt" is entered, this should remain unchanged.

3) If the filename provided is not of the correct format, the program should display a suitable error message and end at this point.

4) The program should then check to see if the file exists using the filename provided. If the file does not exist, a suitable error message should be displayed and the program should end at this point.

5) Next, if the file exists but the file is empty, again a suitable error message should be displayed and the program should end.

6) The file should be read and checked to display crude statistics on the number of characters, words, lines, sentences and paragraphs that are within the file.



Here is the code I have done so far and it doesn't seem to work. Can anybody see why??

Expand|Select|Wrap|Line Numbers
  1. #usr/bin/perl 
  2.  
  3. use strict; 
  4. use warnings; 
  5.  
  6. if ($#ARGV == -1) #no filename provided as a command line argument. 
  7. print("Please enter a filename: "); 
  8. $filename = <STDIN>; 
  9. chomp($filename); 
  10. else #got a filename as an argument. 
  11. $filename = $ARGV[0]; 
  12.  
  13. #perform the specified checks 
  14. #check if filename is valid, exit if not 
  15. if ($filename !~ m^/[a-z]{1,7}\.TXT$/i) 
  16. die("File format not valid\n");) 
  17.  
  18. if ($filename !~ m/\.TXT$/i) 
  19. $filename .= ".TXT"; 
  20.  
  21. #check if filename is actual file, exit if it is. 
  22. if (-e $filename) 
  23. die("File does not exist\n"); 
  24.  
  25. #check if filename is empty, exit if it is. 
  26. if (-s $filename) 
  27. die("File is empty\n"); 
  28.  
  29. my $i = 0; 
  30. my $p = 1; 
  31. my $words = 0; 
  32. my $chars = 0; 
  33.  
  34. open(READFILE, "<$data1.txt") or die "Can't open file '$filename: $!"; 
  35.  
  36. #then use a while loop and series of if statements similar to the following 
  37. while (<READFILE>) { 
  38. chomp;    #removes the input record Separator 
  39. $i = $.;    #"$". is the input record line numbers, $i++ will also work 
  40. $p++ if (m/^$/);   #count paragraphs 
  41. split (/\s+/);    #split sentences into "words" 
  42. $words++     #count all characters except spaces and add to $chars 
  43. $chars += tr/ //c;     #tr/ //c replaces everything in the string with itself, except spaces, and returns the number of such characters replaced 
  44.  
  45.  
  46. #display results 
  47. print "There are $i lines in $data1\n"; 
  48. print "There are $p Paragraphs in $data1\n"; 
  49. print "There are $words in $data1\n"; 
  50. print "There are $chars in $data1\n"; 
  51.  
  52. close(READFILE);
  53.  
Jun 25 '08 #1
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5 Replies


numberwhun
Expert Mod 2.5K+
P: 3,503
First off, the first line in your program is incorrect. You have:

Expand|Select|Wrap|Line Numbers
  1. #usr/bin/perl
  2.  
when what you should have is:

Expand|Select|Wrap|Line Numbers
  1. #!/usr/bin/perl
  2.  
The first two characters are the "#" and "!". They make up the "shbang" (hashbang). You also need the "/" at the beginning of the path as well.

Another issue that I see is:

Expand|Select|Wrap|Line Numbers
  1. split (/\s+/);    #split sentences into "words"
  2.  
This will definitely throw you an error. You are doing a split, but into what? You need to have an array set equal to this, as so:

Expand|Select|Wrap|Line Numbers
  1. my @words;
  2.  
  3. @words = split (/\s+/);   
  4.  
If you don't have something to put the "words" into, an exception is thrown.


Other than that I have two notes. The first, is please use code tags any time you include code in your posting. You can see them in your original posting if you edit it. They are required and not optional in the forums.

Second, when you say you are "getting an error" or "the code produces and error", it is customary to please include the error(s) that you are seeing as we cannot see them otherwise.

Regards,

Jeff
Jun 25 '08 #2

P: 3
Analysing text files to obtain statistics on their content

You are to write a Perl program that analyses text files to obtain statistics on their content. The program should operate as follows:

1) When run, the program should check if an argument has been provided. If not, the program should prompt for, and accept input of, a filename from the keyboard.

2) The filename, either passed as an argument or input from the keyboard, should be checked to ensure it is in MS-DOS format. The filename part should be no longer than 8 characters and must begin with a letter or underscore character followed by up to 7 letters, digits or underscore characters. The file extension should be optional, but if given is should be ".TXT" (upper- or lowercase).

If no extension if given, ".TXT" should be added to the end of the filename. So, for example, if "testfile" is input as the filename, this should become "testfile.TXT". If "input.txt" is entered, this should remain unchanged.

3) If the filename provided is not of the correct format, the program should display a suitable error message and end at this point.

4) The program should then check to see if the file exists using the filename provided. If the file does not exist, a suitable error message should be displayed and the program should end at this point.

5) Next, if the file exists but the file is empty, again a suitable error message should be displayed and the program should end.

6) The file should be read and checked to display crude statistics on the number of characters, words, lines, sentences and paragraphs that are within the file.



I am very new to Perl and have managed to compile this code using examples from various books. Could anyone oversee this coding and see how it could be improved.

Expand|Select|Wrap|Line Numbers
  1. #!/usr/bin/perl 
  2.  
  3. use strict; 
  4. use warnings; 
  5.  
  6. if ($#ARGV == -1) #no filename provided as a command line argument. 
  7. print("Please enter a filename: "); 
  8. $filename = <STDIN>; 
  9. chomp($filename); 
  10. else #got a filename as an argument. 
  11. $filename = $ARGV[0]; 
  12.  
  13. #perform the specified checks 
  14. #check if filename is valid, exit if not 
  15. if ($filename !~ m^/[a-z]{1,7}\.TXT$/i) 
  16. die("File format not valid\n");) 
  17.  
  18. if ($filename !~ m/\.TXT$/i) 
  19. $filename .= ".TXT"; 
  20.  
  21. #check if filename is actual file, exit if it is. 
  22. if (-e $filename) 
  23. die("File does not exist\n"); 
  24.  
  25. #check if filename is empty, exit if it is. 
  26. if (-s $filename) 
  27. die("File is empty\n"); 
  28.  
  29. my $i = 0; 
  30. my $p = 1; 
  31. my $words = 0; 
  32. my $chars = 0; 
  33.  
  34. open(READFILE, "<$data1.txt") or die "Can't open file '$filename: $!"; 
  35.  
  36. #then use a while loop and series of if statements similar to the following 
  37. while (<READFILE>) { 
  38. chomp; #removes the input record Separator 
  39. $i = $.; #"$". is the input record line numbers, $i++ will also work 
  40. $p++ if (m/^$/); #count paragraphs 
  41. $my @t = split (/\s+/); #split sentences into "words" 
  42. $words += @t; #add count to $words 
  43. $chars += tr/ //c; #tr/ //c count all characters except spaces and add to $chars 
  44.  
  45.  
  46. #display results 
  47. print "There are $i lines in $data1\n"; 
  48. print "There are $p Paragraphs in $data1\n"; 
  49. print "There are $words in $data1\n"; 
  50. print "There are $chars in $data1\n"; 
  51.  
  52. close(READFILE);
  53.  
Jun 25 '08 #3

numberwhun
Expert Mod 2.5K+
P: 3,503
First, I distinctly remember asking you to use code tags when posting code in the forums. I even mentioned that it was not an option, but instead a requirement that they be used. This is no longer me asking, this is your only warning. PLEASE use code tags when posting code in the forums!

Second, DO NOT start a new thread on the same exact topic as you previously posted. Simply reply to your post and post your additions. I have merged your two threads accordingly.

Please be sure and read the Guidelines that are posted at the top of this forum as they will tell you the proper way to post in the forums.

As for your issue, it looks as though this is school work, especially since it is formatted as a homework question. It is against this sites guidelines to post your homework here in hopes of getting us to do it for you. Other than the issue you had before, you did not mention any errors this time, so we don't have anything to fix. I believe that optimizing this code is probably part of your assignment (especially since you copied it out of books). You should learn the basics of Perl and examine the code and see if you can first find any ways to optimize it.

Please heed the warning(s) I have provided above as well.

Regards,

Jeff
Jun 25 '08 #4

nithinpes
Expert 100+
P: 410
There are many errors in your code. In line :
Expand|Select|Wrap|Line Numbers
  1. open(READFILE, "<$data1.txt") or die "Can't open file '$filename: $!"; 
  2.  
where are you getting $data1 from? You have assigned filename to $fileneme.
The following line is not correct.
Expand|Select|Wrap|Line Numbers
  1. $my @t = split (/\s+/);
  2.  
The loop for testing file format should come after loop for appending .TXT. Also, there are logical errors in loops for testing existence and size of file. You should use 'unless' instead of 'if'.


Modify the script as below:
Expand|Select|Wrap|Line Numbers
  1. #!usr/bin/perl 
  2.  
  3. use strict; 
  4. use warnings; 
  5.  
  6. my $filename; 
  7. my $i = 0; 
  8. my $p = 1; 
  9. my $words = 0; 
  10. my $chars = 0; 
  11. if ($#ARGV == -1) #no filename provided as a command line argument. 
  12. print("Please enter a filename: "); 
  13. $filename = <STDIN>; 
  14. chomp($filename); 
  15. else #got a filename as an argument. 
  16. $filename = $ARGV[0]; 
  17.  
  18. if ($filename !~ m/\.TXT$/i) 
  19. $filename .= ".txt"; 
  20. #perform the specified checks 
  21. #check if filename is valid, exit if not 
  22. if ($filename !~ m/^[a-z]{1,7}\.TXT$/i) 
  23. die("File format not valid\n");
  24.  
  25.  
  26.  
  27. #check if filename is actual file, exit if it is. 
  28. unless (-e $filename) 
  29. die("File does not exist\n"); 
  30.  
  31. #check if filename is empty, exit if it is. 
  32. unless (-s $filename) 
  33. die("File is empty\n"); 
  34.  
  35.  
  36.  
  37. open(READFILE, "<$filename") or die "Can't open file $filename: $!"; 
  38.  
  39. #then use a while loop and series of if statements similar to the following 
  40. while (<READFILE>) { 
  41. chomp;    #removes the input record Separator 
  42. $i = $.;    
  43. ## 
  44. $p++ if (m/^$/); #count paragraphs 
  45. my @t = split (/\s+/); #split sentences into "words" 
  46. $words += @t; #add count to $words 
  47. $chars += tr/ //c;     #tr/ //c replaces everything in the string with itself, except spaces, and returns the number of such characters replaced 
  48.  
  49.  
  50. #display results 
  51. print "There are $i lines in $filename\n"; 
  52. print "There are $p Paragraphs in $filename\n"; 
  53. print "There are $words words in $filename\n"; 
  54. print "There are $chars characters in $filename\n"; 
  55.  
  56. close(READFILE);
  57.  
Jun 25 '08 #5

KevinADC
Expert 2.5K+
P: 4,059
Second, DO NOT start a new thread on the same exact topic as you previously posted. Simply reply to your post and post your additions. I have merged your two threads accordingly.


Regards,

Jeff
He did the same on the perlguru forum. Obnoxious.
Jun 25 '08 #6

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