CSV-Datei mit Delphi einlesen

[Schokohase]

Hier ein kleines Beispielprojekt

Delphi-Quellcode:

program CsvReader;

{$APPTYPE CONSOLE}
{$R *.res}

uses
  System.Classes,
  System.SysUtils;

type
  TEndOfLineOption = (eolCR, eolLF, eolCRLF);

  TCsvReader = class
  private
    FReader: TStreamReader;
    FQuoteChar: Char;
    FDelimiter: Char;
    FEndOfLine: TEndOfLineOption;
    procedure Initialize();
    function GetEndOfStream: Boolean;
  public
    constructor Create(Stream: TStream); overload;
    constructor Create(Stream: TStream; DetectBOM: Boolean); overload;
    constructor Create(Stream: TStream; Encoding: TEncoding; DetectBOM: Boolean = False; BufferSize: Integer = 4096); overload;
    constructor Create(const Filename: string); overload;
    constructor Create(const Filename: string; DetectBOM: Boolean); overload;
    constructor Create(const Filename: string; Encoding: TEncoding; DetectBOM: Boolean = False; BufferSize: Integer = 4096); overload;
    destructor Destroy; override;

    property Delimiter: Char read FDelimiter write FDelimiter;
    property EndOfLine: TEndOfLineOption read FEndOfLine write FEndOfLine;
    property EndOfStream: Boolean read GetEndOfStream;
    property QuoteChar: Char read FQuoteChar write FQuoteChar;

    procedure OwnStream();

    function ReadLine(): TArray<string>;
  end;

  { TCsvReader }

constructor TCsvReader.Create(Stream: TStream; Encoding: TEncoding; DetectBOM: Boolean; BufferSize: Integer);
begin
  inherited Create();
  Initialize();
  FReader := TStreamReader.Create(Stream, Encoding, DetectBOM, BufferSize);
end;

constructor TCsvReader.Create(Stream: TStream; DetectBOM: Boolean);
begin
  inherited Create();
  Initialize();
  FReader := TStreamReader.Create(Stream, DetectBOM);
end;

constructor TCsvReader.Create(Stream: TStream);
begin
  inherited Create();
  Initialize();
  FReader := TStreamReader.Create(Stream);
end;

constructor TCsvReader.Create(const Filename: string; Encoding: TEncoding; DetectBOM: Boolean; BufferSize: Integer);
begin
  inherited Create();
  Initialize();
  FReader := TStreamReader.Create(Filename, Encoding, DetectBOM, BufferSize);
end;

constructor TCsvReader.Create(const Filename: string; DetectBOM: Boolean);
begin
  inherited Create();
  Initialize();
  FReader := TStreamReader.Create(Filename, DetectBOM);
end;

constructor TCsvReader.Create(const Filename: string);
begin
  inherited Create();
  Initialize();
  FReader := TStreamReader.Create(Filename);
end;

destructor TCsvReader.Destroy;
begin
  FReader.Free();
  inherited;
end;

function TCsvReader.GetEndOfStream: Boolean;
begin
  Result := FReader.EndOfStream;
end;

procedure TCsvReader.Initialize;
begin
  FDelimiter := ',';
  FQuoteChar := '"';
  FEndOfLine := eolCRLF;
end;

procedure TCsvReader.OwnStream;
begin
  FReader.OwnStream();
end;

function TCsvReader.ReadLine: TArray<string>;
var
  str: string;
  c: Char;
  LineDelimiter: string;
  sl: TStringList;
  QuoteCountEven: Boolean;
  EndsWithLineDelimiter: Boolean;
begin
  case EndOfLine of
    eolCR:
      LineDelimiter := #13;
    eolLF:
      LineDelimiter := #10;
    eolCRLF:
      LineDelimiter := #13#10;
  else
    raise Exception.Create('Fehlermeldung');
  end;

  if FReader.EndOfStream then
    raise EInvalidOpException.Create('End of stream');

  str := string.Empty;
  repeat
    c := Char(FReader.Read());
    str := str + c;
    QuoteCountEven := str.CountChar(QuoteChar) mod 2 = 0;
    EndsWithLineDelimiter := str.EndsWith(LineDelimiter);
  until FReader.EndOfStream or (EndsWithLineDelimiter and QuoteCountEven);

  if not QuoteCountEven then
    raise EInvalidOpException.Create('Quote parse error');

  if EndsWithLineDelimiter then
    str := str.Substring(0, str.Length - LineDelimiter.Length);

  sl := TStringList.Create();
  try
    sl.Delimiter := Delimiter;
    sl.StrictDelimiter := True;
    sl.DelimitedText := str;
    Result := sl.ToStringArray();
  finally
    sl.Free();
  end;
end;

procedure Main();
const
  sample = '' + //
    'a,b,c' + sLineBreak + //
    'a,"b",c' + sLineBreak + //
    'a,"b1,b2",c' + sLineBreak + //
    'a,"b1' + sLineBreak + 'b2",c';
var
  s: TStringStream;
  r: TCsvReader;
  l: TArray<string>;
begin
  s := TStringStream.Create(sample);
  try
    r := TCsvReader.Create(s);
    try
      r.Delimiter := ',';
      r.QuoteChar := '"';
      r.EndOfLine := eolCRLF;

      while not r.EndOfStream do
      begin
        l := r.ReadLine();
        WriteLn(string.Join(' | ', l));
      end;

    finally
      r.Free();
    end;
  finally
    s.Free();
  end;
end;

begin
  try
    Main();
  except
    on E: Exception do
      WriteLn(E.ClassName, ': ', E.Message);
  end;
  Readln;

end.

Ausgabe

Code:

a | b | c
a | b | c
a | b1,b2 | c
a | b1
b2 | c