我有這個代碼。我想遍歷數組并為每個條目創建一個新文檔。如果我手動將循環長度設置為它工作正常的行數。我想將它設置為循環數組的長度。但是，.length 屬性始終返回 null。我錯過了什么。我也嘗試過每個循環但沒有運氣。    function createDocument() {    //var headers = Sheets.Spreadsheets.Values.get('fileID', 'A1:Z1');  var studentHistory = Sheets.Spreadsheets.Values.get('fileID', 'A2:Z200');  var templateId = 'fileID';  var documentId;  var dstFolder = DriveApp.getFolderById('folderID');  var length = studentHistory.length;  Logger.log(studentHistory);  Logger.log(length);  //Loop through rows in sheet  for (var i = 0; i < length; i++){     //Get values from sheet row    var date = studentHistory.values[i][0];    var studentName = studentHistory.values[i][1];    var dob = studentHistory.values[i][2];    var pcDoctor = studentHistory.values[i][3];    var address = studentHistory.values[i][4];    var fgName = studentHistory.values[i][5];    var mgName = studentHistory.values[i][6];    var phoneMom = studentHistory.values[i][7];    var phoneDad = studentHistory.values[i][8];    var empMom = studentHistory.values[i][9];    var empDad = studentHistory.values[i][10];    var livesWith = studentHistory.values[i][11];    var childrenInHome = studentHistory.values[i][12];    var childrenNotInHome = studentHistory.values[i][13];    var othersInHome = studentHistory.values[i][14];    var illnesses = studentHistory.values[i][15];    var illnessDetails = studentHistory.values[i][16];    var hospitalizations = studentHistory.values[i][17];    var hospDetails = studentHistory.values[i][18];    var trauma = studentHistory.values[i][19];    var traumaDetails = studentHistory.values[i][20];    var injuries = studentHistory.values[i][21];    var injuryDetails = studentHistory.values[i][22];    var medications = studentHistory.values[i][23];    var additionalComments = studentHistory.values[i][24];    var otherSchools = studentHistory.values[i][25];  }}