为什么Google Apps脚本无法在数组中找到字符串

Question

I want Google Apps Script to convert column names in a spreadsheet into column numbers, but I can't get it to match the column name string. Please can somebody tell me what I can do to make it work. This is my code:

function getCol(columnName){
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Form responses 1");
  var colNames = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0];
  for (var i = 0; i < colNames.length; i++){
    if (colNames[i].toLowerCase() === columnName.toLowerCase()){
      return i;
    }
  throw "Column name "+columnName+" not found in column names "+colNames;
  }
} 

And when I run it looking for the column 'Date Required' for example, this is the error that comes back:

"Column name Date Required not found in column names Def,Date Required,Day of the week,Rooms Required,Purpose Of Event,No. of attendees,Start Time Required,First Names,Surname,Mobile Number,Email,End Time,House & Street,Area,Town/Postcode,Landline,Mobile 2,Age Group,Date of Previous Bookings if any,How did you hear about SouthBank?,Other Requirements,Other,Catering Provisional Enquiry,Additional Access Time Required?,Set Up Access Time,Length of set up time required,Timestamp,,Booking accepted,Form emailed,Added to calendar"

Answer 1

You have the throw statement inside the for loop. You need to move it outside of the for loop. Now you are only testing the first value in the array, in this case 'Def' before calling the throw statement. Since 'Def' is not equal to the parameter columnName, in your case it seems to be 'Date Required', it throws an error.

This is what it should look like and the function should now return 1 if you pass in 'Date Required' as a parameter.

function getCol(columnName){
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Form responses 1");
  var colNames = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0];
  for (var i = 0; i < colNames.length; i++){
    if (colNames[i].toLowerCase() === columnName.toLowerCase()){
      return i;
    }
  }
  throw "Column name "+columnName+" not found in column names "+colNames;
}