I need my pascal program to read and compare data from an external txt
file
lazarus / 16-Databases

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teochris · 2016-01-02 09:40

Hello,

I have builded a pascal program and now I am facing the following
difficulty. In my program I use variables like this

fsarray: array[1..6] of integer;

I have an external .txt file that is in the following format

1#31/12/1997#13#34#38#17#4#12
2#28/12/1997#20#23#30#19#41#8
3#24/12/1997#40#35#24#21#22#3
4#21/12/1997#15#3#38#32#19#20
5#17/12/1997#31#11#22#2#28#16
6#14/12/1997#32#6#19#30#27#4
7#10/12/1997#3#40#15#19#45#18
8#7/12/1997#7#14#31#44#18#14
9#3/12/1997#31#18#42#30#2#17
10#30/11/1997#5#37#42#11#6#7
11#26/11/1997#18#6#28#23#35#5

I need to do some comparisons and checks between my app and the
external file, for example I want to check if fsarray: array[1] is
equal to any of the values in the text file between the second and the
third #

Can this be done or do I have to create a database for such comparison
(I have no idea of how I can create a database, what is the proper
format for the database or even where to start from)? Can you please
give me an example of your proposal?

Any help would be appreciated!

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eny · 2016-01-02 09:56

This should be moved to the homework section.

You can use a TStringList to read the file into memory.
Then you can use for example ExtractWord(...) in the strutils unit to
extract the values you need.

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balazsszekely · 2016-01-02 09:58

I think the most painless solution is to use TStringList, like
this(just don't forget to add sysutils to the uses clauses):
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var  SL,
SLExplode: TStringList;  I, J: Integer;begin  SL :=
TStringList.Create;  try    SL.LoadFromFile('text.txt');    SLExplode
:= TStringList.Create;    try      for I := 0 to SL.Count - 1 do     
begin        Writeln('Line ' + IntToStr(I) + ':');       
SLExplode.Clear;        SLExplode.Delimiter := '#';       
SLExplode.DelimitedText :=  SL.Strings[I];        for J := 0 to
SLExplode.Count - 1 do        begin          writeln('      Item ' +
IntToStr(J) + '  =  ' + SLExplode[J]);          //do whatever you have
to do with SLExplode[J]        end;      end;    finally     
SLExplode.Free;    end;  finally    SL.Free;  end;  Readln;end.

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teochris · 2016-01-02 10:32

Quote from: GetMem on January 02, 2016, 10:58:20 amI think the most
painless solution is to use TStringList, like this(just don't forget
to add sysutils to the uses clauses):

Excellent and very helpful advise and example

Can I also read the .txt file from internet instead of the local disk?

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Jurassic Pork · 2016-01-02 10:37

hello,
you can also load your datas in a stringgrid :
example :
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var myGrid
: Tstringgrid;beginmyGrid := TStringGrid.Create(nil);with mygrid
dobeginLoadFromCSVFile('myTextFile.txt','#',false);Memo1.Append('Cols
: ' + inttoStr(ColCount) + ' - ' +             'Rows : ' +
inttoStr(RowCount));Memo1.Append('First Data Line : ' +             
Cells[2,1] + ' - ' +  Cells[3,1] + ' - ' + Cells[4,1] + ' - ' +      
      Cells[5,1] + ' - ' +  Cells[6,1] + ' - ' + Cells[7,1]);end;// to
be defined 
and maybe use a stream ( ex LoadFromCsvStream) to load from internet.

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balazsszekely · 2016-01-02 10:42

Quote@teochris
Can I also read the .txt file from internet instead of the local
disk?Yes, you can download the file with synapse, indy, etc..Please
search the forum, you will find a lot of examples.

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teochris · 2016-01-02 10:49

Quote from: GetMem on January 02, 2016, 11:42:10 amQuote@teochris
Can I also read the .txt file from internet instead of the local
disk?Yes, you can download the file with synapse, indy, etc..Please
search the forum, you will find a lot of examples.

You were really helpful - THANKS