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Finding parts of strings in http stream

Posted on 1997-10-15
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Last Modified: 2010-04-04
I would like to find a way to extract strings from a stream returned from a http component. The strings i am looking for consists of unknown decimal numbers and there exact location is also unknown. The only thing that is known is a short string tag a unknown number av charcters before the wanted stringsegment.
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Question by:tomasupp
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4 Comments
 
LVL 3

Expert Comment

by:Pegasus100397
ID: 1347610
Tommasupp,

Could you post an example of what this string looks like? In general, the more "unknowns" when parsing a string, the more logic has to be built in to make it understandable to the application.

Also, the type of component your using might be relevant here. I have some code that parses strings from an NNTP component if that might be of value to you.

regards,
Pegasus
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Author Comment

by:tomasupp
ID: 1347611
To be more specific I want to find numerical data from html documents to put in my own database. A typical line (not necessairily in the begining of the stream) would be:


306 | <!-- plugg -->AGA A                |  -0.50 |  123.00 | 123.50 | 123.00 | 123.50 | 122.00 |  183025 |  22515630 |  0.38

where the text 'AGA A' is the known 'code' and the wanted numerical value is 123.00 (the first one). The problem is not with the http component. I am able to 'see' the text stream and put it in a memo-component or a textfile etc. I just need som intelligent way to extract the data I want.

Tomas
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LVL 3

Accepted Solution

by:
Pegasus100397 earned 100 total points
ID: 1347612
procedure TForm1.Button1Click(Sender: TObject);
var iAGA_OffSet,      {Keeps track of where "AGA A" is in the line}
    iSkippy: Integer; {used in loop}
begin
{We assume the text to be parsed is in Memo1}
{further assume that we want to store the parsed values in ListBox1}
With Memo1 DO
  Begin
  While Memo1.Text <> '' DO
     Begin
     iAGA_Offset := Pos('AGA A', Memo1.Text);
      if iAGA_Offset >0 then
       begin
       {Let's throw away anything before the "AGA A" since we don't need it.}
       Memo1.Text := Copy(Memo1.Text, iAGA_Offset,Length(Memo1.Text));
       {since "AGA A" is now at the beginning of the line, set the offset to 1}
       iAGA_Offset := 1;
       {String should now look like "AGA A | -0.50 | 123.00 | 123.50 | 123.00...
        and we need to skip the first two vertical bars to find our value}
       For iSkippy := 1 to 2 Do
           Memo1.Text := Copy(Memo1.Text, Pos('|',Memo1.Text)+1,Length(Memo1.Text));
       {our needed value is now at the beginning of the line, let's add it to
        a list box that contains the parsed values}
       ListBox1.Items.Add(Copy(Memo1.Text,0,Pos('|',Memo1.Text)-1));
       end
      else
       Memo1.Text := ''; {AGA A not found to clear memo for next parse}
     end;
  end;
end;

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Author Comment

by:tomasupp
ID: 1347613
For a quick and relevant answer I give everything I've got...
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