Change of Delimited Text Order in Text File

[Boleeman]

Hi Folks.

Made a small program using 2 listboxes and a command button to change the order of 10 delimited string values (separated by semicolons). Wanted the last word of each line in the text file to be first.

If I change the value of i in    T := RowArray[i].Split(';');      for a specific line it works for that line

Almost like the looping is not working.

I applied the steps:
1.  Load text file in listbox1
2. Make a RowArray for each listbox row.
3  Split each listbox1 row
4. Make a new order of the strings.
5. Loop through the listbox1 by count and add to listbox2.

Here is my code:

Code: Pascal  [Select][+][-]

1. unit delimited;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     bn_doIt: TButton;
16.     ListBox1: TListBox;
17.     ListBox2: TListBox;
18.     procedure bn_doItClick(Sender: TObject);
19.   private
20.  
21.   public
22.  
23.   end;
24.  
25. var
26.   Form1: TForm1;
27.  
28. implementation
29.  
30. {$R *.lfm}
31.  
32. { TForm1 }
33.  
34. procedure TForm1.bn_doItClick(Sender: TObject);
35. var
36.   T, RowArray: array of string;
37.   i : Integer;
38.  
39. begin
40.   ListBox1.Items.LoadFromFile('Test.txt');
41.  
42.   i := 0;
43.   T:= Nil;
44.   RowArray := Nil;
45.   RowArray:= ListBox1.Items.ToStringArray;
46.         begin
47.             for i := 0 to ListBox1.Items.Count - 1 do
48.                 T := RowArray[i].Split(';');
49.                 ListBox2.Items.Add(T[10] + ';' + T[0] + ';' + T[1] + ';' + T[2] + ';' + T[3]
50.              + ';' + T[4] + ';' + T[5] + ';' + T[6] + ';' + T[7] + ';' + T[8] + ';' + T[9]);
51.         end;
52. end;
53.  
54.  
55. end.

[alpine]

Don't you think the

Code: Pascal  [Select][+][-]

1. RowArray := Nil;
2. RowArray:= ListBox1.Items.ToStringArray;

should be before/outside the for loop?

[Boleeman]

Yes I made some changes before and forgot to change that. Still not working (only get the last line).


This part does not increment for i = 0, 1, 2


for i := 0 to ListBox1.Items.Count - 1 do
 
 
      T := RowArray.Split(';');
      ListBox2.Items.Add(T[10] + ';' + T[0] + ';' + T[1] + ';' + T[2] + ';' + T[3]
   + ';' + T[4] + ';' + T[5] + ';' + T[6] + ';' + T[7] + ';' + T[8] + ';' + T[9]);

[alpine]

Yes I made some changes before and forgot to change that. Still not working (only get the last line).

You don't have begin ... end after the for. Only indentation.

[Boleeman]

Tried with

Code: Pascal  [Select][+][-]

1. procedure TForm1.bn_doItClick(Sender: TObject);
2. var
3.   T, RowArray: array of string;
4.   i : Integer;
5.  
6. begin
7.   ListBox1.Items.LoadFromFile('Test.txt');
8.  
9.   i := 0;
10.   T:= Nil;
11.   RowArray := Nil;
12.   RowArray:= ListBox1.Items.ToStringArray;
13.         begin
14.             for i := 0 to ListBox1.Items.Count - 1 do
15.                 T := RowArray[i].Split(';');
16.                 ListBox2.Items.Add(T[10] + ';' + T[0] + ';' + T[1] + ';' + T[2] + ';' + T[3]
17.              + ';' + T[4] + ';' + T[5] + ';' + T[6] + ';' + T[7] + ';' + T[8] + ';' + T[9]);
18.         end;
19. end;
20.  
21.  
22. end.

[alpine]

Try

Code: Pascal  [Select][+][-]

1. procedure TForm1.bn_doItClick(Sender: TObject);
2. var
3.   T, RowArray: array of string;
4.   i: integer;
5.  
6. begin
7.   ListBox1.Items.LoadFromFile('Test.txt');
8.   begin
9.  
10.     i := 0;
11.     T := nil;
12.  
13.     RowArray := nil;
14.     RowArray := ListBox1.Items.ToStringArray;
15.  
16.     for i := 0 to ListBox1.Items.Count - 1 do
17.     begin
18.       T := RowArray[i].Split(';');
19.       ListBox2.Items.Add(T[10] + ';' + T[0] + ';' + T[1] + ';' +
20.         T[2] + ';' + T[3] + ';' + T[4] + ';' + T[5] + ';' + T[6] + ';' +
21.         T[7] + ';' + T[8] + ';' + T[9]);
22.     end;
23.   end;
24. end;

[Boleeman]

Yes that works. Wow. Thanks.

Still learning. Tried all sorts of combinations.


 My Begin and End were all over the place. Now I see where I went wrong.


Thanks Alpine for your help.

[alpine]

No problem.
You can do it even better by using dynarray intrinsics (Length, Low, High, etc.).

Code: Pascal  [Select][+][-]

1. procedure TForm1.bn_doItClick(Sender: TObject);
2. var
3.   T, RowArray: array of string;
4.   i, j: integer;
5.   S: String;
6. begin
7.   ListBox1.Items.LoadFromFile('Test.txt');
8.   begin
9.  
10.     i := 0;
11.     T := nil;
12.  
13.     RowArray := nil;
14.     RowArray := ListBox1.Items.ToStringArray;
15.  
16.     for i := 0 to ListBox1.Items.Count - 1 do
17.     begin
18.       T := RowArray[i].Split(';');
19.       S := '';
20.       if Length(T) > 0 then
21.       begin
22.         S := T[High(T)];
23.         for j := 0 to High(T) - 1 do
24.           S := S + ';' + T[j];
25.       end;
26.       ListBox2.Items.Add(S);
27.     end;
28.   end;
29. end;  

Thus not required each line to have exactly 10 fields.

[Boleeman]

Wow. Even better.

I actually wanted to use string arrays without listboxes but needed something simple to start off with.

Tried out your new code. Works well. Like seeing how things can be done in different ways.

Thanks for the updated code. Much appreciated.


So    S := T[High(T)];      gives the   highest Array element of array T

Did not know this.

Thought that typing out:
T[10] + ';' + T[0] + ';' + T[1] + ';' +
            T[2] + ';' + T[3] + ';' + T[4] + ';' + T[5] + ';' + T[6] + ';' +
            T[7] + ';' + T[8] + ';' + T[9]);

was a bit too much and mistake prone.


I will test the other way as well like    S := T[Low(T)];    would give lowest Array element of array T

Would you use this if you wanted to go the other way like with letter at the back again.

Crossing;1.25;1.5;8;0.1;1.45;0.45;350;8;0;16711935

to

1.25;1.5;8;0.1;1.45;0.45;350;8;0;16711935;Crossing

[alpine]

I will test the other way as well like    S := T[Low(T)];    would give lowest Array element of array T

Low(T) for a dynamic array is 0, it makes sense for declared arrays where the lower bound can be something different.
 

Would you use this if you wanted to go the other way like with letter at the back again.

Crossing;1.25;1.5;8;0.1;1.45;0.45;350;8;0;16711935

to

1.25;1.5;8;0.1;1.45;0.45;350;8;0;16711935;Crossing

Then you should probably change this

Code: Pascal  [Select][+][-]

1.       ...
2.       if Length(T) > 0 then
3.       begin
4.         S := T[High(T)];
5.         for j := 0 to High(T) - 1 do
6.           S := S + ';' + T[j];
7.       end;
8.       ...

to:

Code: Pascal  [Select][+][-]

1.       ...
2.       if Length(T) > 0 then
3.       begin
4.         for j := 1 to High(T) do // <-- from 1 to the highest
5.           S := S + T[j] + ';'; // <-- put the semicolon after
6.         S := T[0];
7.       end;
8.       ...

[Boleeman]

Small correction:

      if Length(T) > 0 then
       begin
         for j := 1 to High(T) do // <-- from 1 to the highest
           S := S + T[j] + ';'; // <-- put the semicolon after
          S := S + T[0];
       end;             


Wow. Thanks once again Alpine.

[alpine]

Sorry for the mistake, but obviously you've got the idea

[Boleeman]

Apline. Thanks for all your help. It was appreciated.

A helping hand helped me to understand what I was doing wrong.
Felt like I was going round in circles at the time.

[ASerge]

Code: Pascal  [Select][+][-]

1. procedure TForm1.bn_doItClick(Sender: TObject);
2. var
3.   L: TStringList;
4.   S, Last: string;
5.   A: TStringArray;
6. begin
7.   ListBox2.Clear;
8.   L := TStringList.Create;
9.   try
10.     L.LoadFromFile('test.txt');
11.     for S in L do
12.     begin
13.       A := S.Split(';');
14.       if A = nil then
15.         Continue;
16.       Last := A[High(A)];
17.       Insert(Last, A, 0);
18.       Delete(A, High(A), 1);
19.       ListBox2.Items.Append(''.Join(';', A));
20.     end;
21.   finally
22.     L.Free;
23.   end;
24. end;

[Zvoni]

Serge, you sure about Line 17?
Because docs say something different --> https://www.freepascal.org/docs-html/rtl/system/insert.html
Either insert a String "Source" into String "S" at Position, or insert DynArray Source into DynArray S at Index

Your code looks like "Insert String Source into DynArray S at Index".

Or is this undocumented behavior?