?
Solved

Deleting duplicates from an array

Posted on 1998-09-25
5
Medium Priority
?
289 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
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 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 400 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

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

Are you an Exchange administrator employed with an organization? And, have you encountered a corrupt Exchange database due to which you are not able to open its EDB file. This article will explain all the steps to repair corrupt Exchange database.
Want to know how to use Exchange Server Eseutil command? Go through this article as it gives you the know-how.
This is my first video review of Microsoft Bookings, I will be doing a part two with a bit more information, but wanted to get this out to you folks.
Sometimes it takes a new vantage point, apart from our everyday security practices, to truly see our Active Directory (AD) vulnerabilities. We get used to implementing the same techniques and checking the same areas for a breach. This pattern can re…
Suggested Courses

719 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