TStringList 常用操作

//TStringList 常用方法与属性:
 var
  List: TStringList;
  i: Integer;
begin
  List := TStringList.Create;
  List.Add('Strings1');           {添加}
  List.Add('Strings2');
  List.Exchange(0,1);             {置换}
  List.Insert(0,'Strings3');      {插入}
  i := List.IndexOf('Strings1');  {第一次出现的位置}
  List.Sort;                      {排序}
  List.Sorted := True;  {指定排序}
  List.Count;                     {总数}
  List.Text;                      {文本集合}
  List.Delete(0);                 {删除, 0是第一个数据}
  List.LoadFromFile('c:\tmp.txt');{打开}
  List.SaveToFile('c:\tmp.txt');  {保存}
  List.Clear;                     {清空}
  List.Free;                      {释放}
end;

---

//读入字符串
var
  List: TStringList;
begin
  List := TStringList.Create;
  List.CommaText := 'aaa,bbb,ccc,ddd';
  //相当于: List.Text := 'aaa' + #13#10 + 'bbb' + #13#10' + 'ccc' + '#13#10' + 'ddd';

  ShowMessage(IntToStr(List.Count));  //4
  ShowMessage(List[0]);  //aaa

  List.Free;
end;

---

//置换分隔符
var
  List: TStringList;
begin
  List := TStringList.Create;
  List.Delimiter := '|';
  List.DelimitedText := 'aaa|bbb|ccc|ddd';

  ShowMessage(IntToStr(List.Count));  //4
  ShowMessage(List[0]);  //aaa

  List.Free;
end;

---

//类似的哈希表操作法
var
  List: TStringList;
begin
  List := TStringList.Create;

  List.Add('aaa=111');
  List.Add('bbb=222');
  List.Add('ccc=333');
  List.Add('ddd=444');

  ShowMessage(List.Names[1]);  //bbb
  ShowMessage(List.ValueFromIndex[1]);  //222
  ShowMessage(List.Values['bbb']);  //222

  //ValueFromIndex 可以赋值:
  List.ValueFromIndex[1] := '2';
  ShowMessage(List[1]);  //bbb=2

  //可以通过 Values 赋值:
  List.Values['bbb'] := '22';
  ShowMessage(List[1]);  //bbb=22

  List.Free;
end;

---

//避免重复值
var
  List: TStringList;
begin
  List := TStringList.Create;

  List.Add('aaa');

  List.Sorted := True;  //需要先指定排序
  List.Duplicates := dupIgnore;  //如有重复值则放弃

  List.Add('aaa');

  ShowMessage(List.Text);  //aaa

  //Duplicates 有3个可选值:
  //dupIgnore: 放弃;
  //dupAccept: 结束;
  //dupError: 提示错误.

  List.Free;
end;

---

//排序与倒排序
{排序函数}
function DescCompareStrings(List: TStringList; Index1, Index2: Integer): Integer;
begin
  Result := -AnsiCompareText(List[Index1], List[Index2]);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  List: TStringList;
begin
  List := TStringList.Create;

  List.Add('bbb');
  List.Add('ccc');
  List.Add('aaa');

  //未排序
  ShowMessage(List.Text);  //bbb ccc aaa

  //排序
  List.Sort;
  ShowMessage(List.Text);  //aaa bbb ccc

  //倒排序
  List.CustomSort(DescCompareStrings);  //调用排序函数
  ShowMessage(List.Text);  //ccc bbb aaa

  //假如:
  List.Sorted := True;
  List.Add('999');
  List.Add('000');
  List.Add('zzz');
  ShowMessage(List.Text);  //000 999 aaa bbb ccc zzz
end;

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