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example code for parsing TAB-delimited text file
(minor adjustments necessary for comma-delimited...)
Date sent: Fri, 02 Apr 1999 10:30:27 -0500
From: Stephen Posey <slposey@concentric.net>
To: Delphi@Kyler.com
Subject: Re: Loading tab-delimited files?
Send reply to: Delphi@Kyler.com
dB_Consultancy wrote:
>
> On Fri, 02 Apr 1999 09:49:30 +0200, Thomas Sundberg wrote:
>
> >Explore the datapump utility that comes with Delphi. Or do it
> >yourself with readln in a while loop (while not eof), parse the
> >line for tab and brake it apart and store each part in the db.
>
> Sorry, But I never used files in applications (only registry for
> settings).
> Could you be so nice to sent me example source code?
> How to read a tab-delimited textfile in Delphi?
> (it will have 4-5 colums)
>
> I will aperciate this very much...
Hmmmm, I'd recommend studying basic Pascal a bit before you attempt much
more sophisticated Delphi work. There's plenty of good texts out there
for that; though I'd recommend a book that deals specifically with
Borland's particular dialect.
Anyways, here's some basic code to read a tab delimited text file:
-------------------->8 cut here 8<--------------------
procedure ParseLine( TheLine: string; List: TStrings ) ;
// split a tab delimited line of text into
// substrings in List
const
TAB = #9 ; // standard ASCII/ANSI char code for Tab
var
P: longint ; // where is next Tab found?
Temp: string ; // remainder of string
begin
List.Clear ; // clear last set
Temp := TheLine ; // save line
P := Pos( TAB, Temp ) ; // find first Tab char
if P = 0 then // account for no Tabs:
P := Length( Temp ) ; // add whole string to List
while P > 0 do
begin
List.Add( Copy( Temp, 1, P - 1 )) ; // append substring to list
Temp := Copy( Temp, P + 1, Length( Temp ) - P ) ; // shorten Temp
P := Pos( TAB, Temp ) ; // find next Tab char
end ;
end ;
procedure DoStuffWithList( LineList: TStrings ) ;
var
i: integer ;
begin
for i := 0 to LineList.Count - 1 do
{ here's where you work with the parsed items from a line }
end ;
var
TheFile: TextFile ; // tab delimited text file
ALine: string ; // A line from the file
TheList: TStringList ; // List to store parsed items
begin
TheList := TStringList.Create ;
// associate file with disk file
AssignFile( TheFile, 'FILENAME.TXT' ) ;
// prepare file for reading
Reset( TheFile ) ;
while not EOF( TheFile ) do // as long as there's more file
begin
ReadLn( TheFile, ALine ) ; // get a line
ParseLine( ALine, TheList ) ; // split into substrings
DoStuffWithList( TheList ) ; // use the substrings
end ;
// cleanup
CloseFile( TheFile ) ;
TheList.Free ;
end ;
-------------------->8 cut here 8<--------------------
Note that this code is untested, it does no error checking, and the
parsing is very simple minded (it will likely have trouble with multiple
tabs); but this should get you started.
HTH
Stephen Posey
slposey@concentric.net
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