Parsen von Seitenzahlen

[Jens01]

Da ich derartiges in meinem Projekt benötige, habe ich den Ansatz von alzaimar übernommen. Ich nutze aber eine Integerliste. Zusätzlich habe ich eine Umkehrung mit CreateNumberString hinzugefügt. Hier wird aus einer Integerliste ein String erstellt.
Vielleicht kann es jemand irgendwann mal gebrauchen.
Gruss Jens

Delphi-Quellcode:

unit tools.ParseNumbers;
// http://www.delphipraxis.net/934335-post7.html

interface

uses
  System.Generics.Collections;

function ExtractString(Var aString: string; const aDelimiter: string): string;
function CreateNumberList(aNumberDesc: string; aNumberList: TList<Integer>): Boolean;
procedure CreateNumberString(var aNumberDesc: string; aNumberList: TList<Integer>);

const
  ValidCharsString = ' ,;-0123456789';

implementation

uses
  System.SysUtils, System.StrUtils;

function ExtractString(Var aString: string; const aDelimiter: string): string;
Var
  P: Integer;
Begin
  P := Pos(aDelimiter, aString);
  If P = 0 Then
  Begin
    Result  := Trim(aString);
    aString := '';
  End
  Else
  Begin
    Result  := Trim(Copy(aString, 1, p - 1));
    aString := Trim(Copy(aString, p + Length(aDelimiter), MaxInt));
  End
End;

procedure TrimString(var s: string);
begin
  s := Trim(s);
  s := ReplaceStr(s, ' -', '-');
  s := ReplaceStr(s, '- ', '-');
  s := ReplaceStr(s, ',', ';');
  s := ReplaceStr(s, ' ;', ';');
  s := ReplaceStr(s, '; ', ';');
  s := ReplaceStr(s, ' ', ';');
end;

function CreateNumberList(aNumberDesc: string; aNumberList: TList<Integer>): Boolean;
Var
  numberDesc, rangeStart: String;
  number, p, q          : Integer;
Begin
  aNumberList.Clear;
  TrimString(aNumberDesc);

  While aNumberDesc <> '' do
  Begin
    numberDesc := ExtractString(aNumberDesc, ';');

    If TryStrToInt(numberDesc, number) Then
      aNumberList.Add(number)
    else
    Begin
      rangeStart := ExtractString(numberDesc, '-');
      If TryStrToInt(numberDesc, q) And TryStrToInt(rangeStart, p) and (p <= q) Then
        For number := p to q Do
          aNumberList.Add(number)
      Else
        Exit(False);
    End
  End;
  Result := True;
End;

procedure CreateNumberString(var aNumberDesc: string; aNumberList: TList<Integer>);
var
  i: Integer;
begin
  if aNumberList.Count = 0 then
    Exit;
  aNumberDesc := '';
  aNumberList.Sort;
  i := 0;
  while (i < aNumberList.Count) do
  begin
    if (i + 2 < aNumberList.Count) and (aNumberList[i] + 1 = aNumberList[i + 1]) and
      (aNumberList[i] + 2 = aNumberList[i + 2]) then
    begin
      aNumberDesc := aNumberDesc + IntToStr(aNumberList[i]) + '-';
      while (i + 1 < aNumberList.Count) and (aNumberList[i] + 1 = aNumberList[i + 1]) do
        Inc(i);
      aNumberDesc := aNumberDesc + IntToStr(aNumberList[i]);
    end
    else
    begin
      aNumberDesc := aNumberDesc + IntToStr(aNumberList[i]);
    end;

    Inc(i);
    if i + 1 < aNumberList.Count then
      aNumberDesc := aNumberDesc + ';';
  end;
end;

end.