Loading Only Certain Columns of a CSV File

[Jade]

I am New to Lazarus and I have figured out how to load my CSV file with the SdfDataSet but I can not figure out how to display only certian parts of the CSV file. I only want to read in Col1, Col3, and Col34 of my file into my Grid. I have tried with a DataBaseGrid and a StringGrid. The DataGrid I have gotten to read just the first column but the other ones i can not figure out. Any help would be appreciated.

[Almir.Bispo]

Hi ! I'm Lazarus and csv expert.
You can do like this:

Code: Pascal  [Select][+][-]

1. procedure load(csvf,csvd:string);
2. var s,d,res:tstringlist;
3.        i:integer;
4. begin
5. s:=tstringlist.create;
6. d:=tstringlist.create;
7. res:=tstringlist.create;
8. d.delimiter:=char(';'); //define delimiter used on csv
9. s.loadfromfile(csvf);//file (csv table) loaded
10. for i:= 0 to s.count-1 do
11. begin
12. d.delimitedtext:=s.strings[i]; //each row of file (table)
13. res.add(d.strings[0]);//define wich column by index number "zero" is the first column
14. end;
15. res.savetofile(csvd);
16.  
17. res.free;
18. s.free;
19. d.free;
20.  
21. end;
22. //how to use
23. //load('c:\origenal.csv','c:\destin.csv');
24. //sdf.active:=false;
25. //sdf.filename:='c:\destin.csv';
26. //sdf.active:=true;
27.  

But if do you want to work with csv like a true Database System,I guess you know the NoSQL CSV Comp DB.
The solution is like this:

Code: Pascal  [Select][+][-]

1. var CQL:Stringlist;
2.       Column:integer;
3. begin
4. CQL:=Tstringlist.create;
5. //what column to list?
6. Column:= 0;//the first colmun
7. //CQL Command
8. CQL.add('{csv_table;@listar;0;0;0;0;query='+ inttostr(Column) +';destino=0}');
9.  
10. //save to imput os database system
11. CQL.savetofile(application.location+'inpout_comp.exe');
12. //execute the csv parser database system
13. shellexecute(handle,pchar('open'),pchar(application.location+'CSV_PARSER.exe'),nil,nil,0);
14. //wait execution
15. //it depend on SO latency
16. while not fileexiste('lock.inf') do begin {do nothing} end;
17. while  fileexiste('lock.inf') do begin {do nothing} end;
18. SDF.active:=false;
19. SDF.filename:='csv_table.que'; //result table
20. SDF.Active:=true;
21. end;
22.  

//The cql code is like:

Code: Javascript  [Select][+][-]

1. {
2.     path\csv_table;
3.     @listar;
4.     0;
5.     0;
6.     0;
7.     0;
8.     query=0;//define the Column here
9.     destino=0
10. }
11.  

There are exemple with Lazarus and NoSQL http://adltecnologia.blogspot.com.br

[Jade]

thank you I actually finally got it to read i had the delimiter set to ; and my CSV file was separated by ,.
But any help on my new question i just posted would be appreciated.