Solved

Deleting duplicates from an array

Posted on 1998-09-25
5
273 Views
Last Modified: 2010-04-16
Lets say you have read 30 names from a file into an array with a format like  names: array[1..40] of string[30]; and there are a number of of duplicates in the file and therefor also the array-as you have read the names into the array- please could you write a procedrue which goes through the array and removes all duplicates from the array.
Thanks

 
0
Comment
Question by:koopa
  • 3
  • 2
5 Comments
 

Author Comment

by:koopa
ID: 1215685
Adjusted points to 100
0
 

Author Comment

by:koopa
ID: 1215686
Please could you reply to the question as soon as possible as I am writing exams on this work in about two weeks
0
 
LVL 5

Accepted Solution

by:
scrapdog earned 100 total points
ID: 1215687
Here is a procedure that will remove duplicate strings from an array.  It will work with your example (array[1..40] of string[30]), or with any array of strings.  Just define it in the type declaration.

-----------------------------------

{written by scrapdog 9/25/98}


type
  t_string_array = array[1..40] of string[30];

procedure remove_duplicates(var s :t_string_array;
                            var size :integer);

var
  i,j  :integer;

begin
  for i := 1 to size do
    for j := i+1 to size do
      if s[i] = s[j] then s[j] := '';      {this loop tests for duplicates}
  j := 1;
  for i := 1 to size do
    if s[i] <> '' then begin               {this loop removes them}
      s[j] := s[i];
      j := j + 1;
    end;
  size := j;
end;

---------------------------------

The procedure accepts as parameters the array and its size.  It will return the edited array and its new size.  For example, if, before you call, your array is of size 40 and contains 4 duplicates, the statements

size := 40;
remove_duplicates(x_array, size);

will remove the duplicates from the array, and 'size' will now equal 36, and only elements 1 to 36 of the array will be relevant.

Let me know if you don't understand something.


~scrappy

 

0
 
LVL 5

Expert Comment

by:scrapdog
ID: 1215688
Additional note:  in the example I gave you, it might be hard to read because of the font that experts-exchange uses in its answers.

In the line that looks like this:

if s[i] = s[j] then s[j] := '';


it is important to point out that these are two APOSTROPHES with NO space in between them, *NOT* a quotation mark.  The same goes for the line that is 3 lines below it.  Hopefully you weren't confused by this.

0
 

Author Comment

by:koopa
ID: 1215689
Thank you for the brilliant answer it helped me alot !
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

What does UTC stand for?  “Coordinated Universal Time” – Think of this as the true time on Planet Earth that never changes with the exception of minor leap seconds here and there to account for the changes in the planet's rotation.   What does th…
Note: This is the third blog post in a series on email clearinghouses (https://www.xmatters.com/alert-management/blog-email-has-failed-us?utm_campaign=70138000000ydLoAAI&utm_source=exex&utm_medium=article&utm_content=blog-post).   We’ve been talki…
This Micro Tutorial hows how you can integrate  Mac OSX to a Windows Active Directory Domain. Apple has made it easy to allow users to bind their macs to a windows domain with relative ease. The following video show how to bind OSX Mavericks to …
In this video I am going to show you how to back up and restore Office 365 mailboxes using CodeTwo Backup for Office 365. Learn more about the tool used in this video here: http://www.codetwo.com/backup-for-office-365/ (http://www.codetwo.com/ba…

911 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

21 Experts available now in Live!

Get 1:1 Help Now