Delphi字符截取函数LeftStr/MidStr/RightStr使用

uses StrUtils

// 测试
procedure TfrmMain.btnStrClick(Sender: TObject);
var
  info: string;
begin
  try
    info:= 'delphi is a rap';
    mmLine.Lines.Add(LeftStr(info, 5)); //从左往右截取，长度是5
    mmLine.Lines.Add(MidStr(info, 5, 2)); //从第5个字符开始截取，长度是2
    mmLine.Lines.Add(RightStr(info, 5));  //从右往左截取，长度是5
  finally

  end;
end;