String Conversion

[pentilisea]

Haya,
still struggling with Syntax ....

Got a txt file to load into a ListBox.

******************
  OpenDialog1.Filter:='txt-Dateien|*.txt';
  if OpenDialog1.Execute then
  ListBox1.Items.LoadFromFile(OpenDialog1.Filename);
*****************

This works OK, but now I need to eliminate certain Items from ListBox1.
The txt files have lines witn Numbers (Integers) and Lines with ASCI (zUklog ---)

I want to deleta all Items containing Characters and
keep all Items containing a Number (1,2,3,4)

Got lost.

************************
for i:=ListBox1.Items.Count - 1 downto 0 do
      if ListBox1.Items :=  ???????????   then               
      ListBox1.Items.Delete(i);
************************

Whatever I am writing instead of the ?????? does not work.

While loading the File the sorting could be done also ....

Would appreciate your hints....

Klaus
 

[dseligo]

From your question it isn't clear if you want to delete all lines that whole line is a number or if only contain numbers ('A123B' vs. '123').
Also it isn't clear if you only want digits 1, 2, 3, 4.
Give examples of what you want deleted and what you want to keep.

If you need whole line to be integer number you can do it like this:

Code: Pascal  [Select][+][-]

1. var iTest: Integer;
2.  
3. for i:=ListBox1.Items.Count - 1 downto 0 do
4.   if not TryStrToInt(ListBox1.Items[i], iTest) then
5.     ListBox1.Items.Delete(i);

[pentilisea]

Thanks for the fast answer.

The content looks like this:

Datum: 02.03.2022
Version: 1.01
********** Gewinnzahlen **********
S  Z  R
      23
      16
35     
      3
      19
2     
8     
15     
      1
      23

***************************

Now only the numbers, no spaces or text should be selected.

Klaus

[pentilisea]

Dear dseligo,
thanks so much, works like a charm....

Klaus

[dseligo]

Dear dseligo,
thanks so much, works like a charm....

Klaus

I am glad it works for you.

If you need to clear white spaces from beginning and end of string, you could use function Trim (https://www.freepascal.org/docs-html/rtl/sysutils/trim.html), like this:

Code: Pascal  [Select][+][-]

1.   var iTest: Integer;
2.  
3.   for i:=ListBox1.Items.Count - 1 downto 0 do begin
4.     ListBox1.Items[i] := Trim(ListBox1.Items[i]);
5.     if not TryStrToInt(ListBox1.Items[i], iTest) then
6.       ListBox1.Items.Delete(i);
7.   end;

[KodeZwerg]

Just a little performanter when you want to trim.

Code: Pascal  [Select][+][-]

1. var iTest: Integer;
2.  
3. for i:=ListBox1.Items.Count - 1 downto 0 do
4.   if not TryStrToInt(ListBox1.Items[i], iTest) then
5.     ListBox1.Items.Delete(i)
6.     else
7.     ListBox1.Items[i] := Trim(ListBox1.Items[i]);

[dseligo]

Just a little performanter when you want to trim.

Code: Pascal  [Select][+][-]

1. var iTest: Integer;
2.  
3. for i:=ListBox1.Items.Count - 1 downto 0 do
4.   if not TryStrToInt(ListBox1.Items[i], iTest) then
5.     ListBox1.Items.Delete(i)
6.     else
7.     ListBox1.Items[i] := Trim(ListBox1.Items[i]);

Actually this is wrong. If his strings have spaces after the number your code will delete them, and my code will leave them.

@pentilisea: If you want strings to be as they are in the file, then move Trim function to comparison:

Code: Pascal  [Select][+][-]

1. for i:=ListBox1.Items.Count - 1 downto 0 do
2.   if not TryStrToInt(Trim(ListBox1.Items[i]), iTest) then
3.     ListBox1.Items.Delete(i);

[TRon]

Just a little performanter when you want to trim.

Code: Pascal  [Select][+][-]

1. var iTest: Integer;
2.  
3. for i:=ListBox1.Items.Count - 1 downto 0 do
4.   if not TryStrToInt(ListBox1.Items[i], iTest) then
5.     ListBox1.Items.Delete(i)
6.     else
7.     ListBox1.Items[i] := Trim(ListBox1.Items[i]);

Actually this is wrong. If his strings have spaces after the number your code will delete them, and my code will leave them.

@pentilisea: If you want strings to be as they are in the file, then move Trim function to comparison:

Code: Pascal  [Select][+][-]

1. for i:=ListBox1.Items.Count - 1 downto 0 do
2.   if not TryStrToInt(Trim(ListBox1.Items[i]), iTest) then
3.     ListBox1.Items.Delete(i);

Based on your first trim example the above statements/code is very confusing. Are you sure you got things right dseligo ?

Actually this is wrong. If his strings have spaces after the number your code will delete them, and my code will leave them.

TryStrtoInt does not care about spaces, hence KodeZwerg's code trims strings in the listbox /only/ when they are not deleted (which to me seems the most efficient way of trimming existing items in the listbox) while your first code always trims any string and your second example only supplies a trimmed string to TryStrToInt()

[dseligo]

Based on your first trim example the above statements/code is very confusing. Are you sure you got things right dseligo ?

Yes, I am sure, I just tried it.

TryStrtoInt does not care about spaces, hence KodeZwerg's code trims strings in the listbox /only/ when they are not deleted (which to me seems the most efficient way of trimming existing items in the listbox) while your first code always trims any string and your second example only supplies a trimmed string to TryStrToInt()

TryStrToInt doesn't care about spaces in front of number, but it cares about space after.

Try this code:

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2. var i: Integer;
3. begin
4.   If TryStrToInt('1 ', i) then ShowMessage('dseligo is wrong')
5.                           else ShowMessage('dseligo is right');
6. end;

I tried it, guess what is shown?

Lazarus 2.2.4 (rev lazarus_2_2_4) FPC 3.2.2 x86_64-win64-win32/win64

[Zvoni]

To me, OP's sample file-content looks like something with Columns (CSV?)
And what is that "S Z R"?

In any case: If it's really just the numeric data he wants, please note, he has a duplicate --> 23 is twice in the file, and both times as if it's in Column R
Bottom line: I'm not so sure about everything said, considering "Gewinnzahlen" sounds like Lottery, and Lottery is usually WITHOUT repeat/duplicates

[TRon]

TryStrToInt doesn't care about spaces in front of number, but it cares about space after.

You are correct.

Try this code:

I tried it, guess what is shown?

Indeed, I was wrong while your statement that TryStrToInt does case about whitespace /after/ a number is correct. Sorry for the confusion.

[pentilisea]

Hi Guys,
thanks for the multiple replies, didn't expect all this.

For more understanding: Its Roulette, not Lottery.
I wrote some extensive Gambas3 and am quite at home.
However, I need a bettter integration to Windows, but I'm still struggling with the elevated complecity in Lazarus.

thanks again
Klaus