Steema Central

Posted: **Wed Jul 14, 2021 10:50 am**

I am using TeeGrid, and TStringsData. I would like to read a CSV file. Is there a function or procedure in teeGrid or TStringsData that provides this? I have scanned through the documentation and source code and did not see any. Most commercial grids like TMS's TAdvStringGrid have a LoadFromCSV function to facilitate this important feature.

I have searched but did not find a similar function in TeeGrid to TStringsData.

In another forum post I saw, Teechart support says to read the CSV manually. Building a robust CSV reader can be complicated. I would prefer something of production-grade and supported by TeeGrid/TeeChart since reading in CSV (tab and delimited files) files are very common.

I know TeeBi have a CSV import function: http://www.teechart.net/docs/teebi/tuto ... -CSV-data/

but I am not using TeeBI as it seems to be no longer developed.

What would be the recommended option?

Thanks!

Posted: **Thu Jul 15, 2021 7:00 am**

Just to agree with beowulf68, the ability to quickly read-in large CSV-files
(with the ability to specify a separator other than comma too) would be really neat.
Was also a user of the grid you mention but switched to TeeGrid due to
the exorbitant pricing and other reasons.

.
regards, Sami.

Posted: **Thu Jul 15, 2021 7:46 am**

Thanks Jonsafi!

I am switching to TeeGrid due to performance.

I tried loading 284K lines and 35 columns dataset (standard credit card fraud dataset for machine learning). The performance is like 2 secs load for TeeGrid vs 10s of seconds for standard TStringGrid and others...

I used the excellent CSV library from Vladimir Nikitenko - Delphi CSV File and String Reader Classes
https://www.codeproject.com/tips/783493 ... er-classes

I "read the CSV manually" into a TStringsData and then assigned it to TeeGrid.Data

Super fast!

It would however be great if TeeGrid and TStringsData can have a native CSV reader. Given the performance of TeeGrid, I am confident the performance will be just as fantastic.

Posted: **Thu Jul 15, 2021 1:35 pm**

Thanks for the CSV tip, Beowulf68! To read in a large CSV-file
(so-called Harvard flight dataset, several GBs),
and to display it on a grid based on TVirtualModeData,
I first read the file into a memory structure (TStringList).
Then at the OnGetCellData event, parsed the
TStringList and assigned each field to
the column/row variables for OnGetCellData .

If the CSV were integrated at the component level,
it would be blazing fast as you point out!

Posted: **Fri Jul 16, 2021 2:45 am**

Jonsafi

Why not use TStringsData instead of TStringList? I believe it does the OnGetCell for you automatically... you just need to read your CSV data into the TStringsData[Col,Row] as usual for stringgrids.

Also because it is a "matrix" structure already, you can do various manipulation like missing values, AVG, STDDEV etc which may be difficult in a TStringList structure.

Code: Select all

2) "TStringGrid" emulator with TStringsData class

  Derived from TVirtualModeData, maintains an internal array of strings, one for
  each cell in the grid.

  Usage:

    var Data : TStringsData;
    Data:= TStringsData.Create; // optional params: Create(5,4)

    // Set size
    Data.Columns:= 5;
    Data.Rows:= 4;

    // Set data to grid
    TeeGrid1.Data:= Data;

    // Set header texts
    Data.Headers[1]:='Company';

    // Set cell values
    Data[1,1]:= 'Steema';
}

Posted: **Fri Jul 16, 2021 9:30 am**

Indeed Beowulf68, used something very similar to your code
for displaying a smaller sized dataset, works very nicely

However, to handle huge CSV-files (even hundreds of millions of rows), I believe the
TVirtualModeData is the one to use. It does not pre-allocate the
data to my understanding, but only displays it when its turn comes
in the grid, using the event OnGetCell:

Code: Select all

Var  
Data_tee_G : TVirtualModeData;

  Data_tee_G                    := TVirtualModeData.Create(nr_cols,nr_rows,60); // just to allocate some memory
  Data_tee_G.OnGetValue := AMain.GetCell; // the OnGetCell event must be fed the correct cell to show.

Steema Central

TeeGrid/TStringsData missing LoadFromCSV ???

TeeGrid/TStringsData missing LoadFromCSV ???

Re: TeeGrid/TStringsData missing LoadFromCSV ???

Re: TeeGrid/TStringsData missing LoadFromCSV ???

Re: TeeGrid/TStringsData missing LoadFromCSV ???

Re: TeeGrid/TStringsData missing LoadFromCSV ???

Re: TeeGrid/TStringsData missing LoadFromCSV ???