如何从 Google Apps 脚本中的列表中获取唯一项？

Question

I have this code snippet:

function getTimeFrames(){
  var ss = SpreadsheetApp.getActive();
  var cell = ss.getRange("C1").getValue();
  Logger.log(cell);
  
  var s = ss.getSheetByName(cell).getRange("M2:M");
  var unique = new Set(s.getValues());
  
  unique.forEach(x => Logger.log(x))
}

This code would be called from a Google Sheets spreadsheet which serves as an UI, where the C1 cell would be a name of a sheet used for storing data. In that sheet I have a column (M) that I need to get the unique values out of in order to store in a drop-down in the UI sheet.

The problem I have is that I can't get the unique values part working at all. Throughout my experimentation, I would either get a list of all the values of column M or no Logging output at all.

Any help is greatly appreciated!

Answer 1

Try

function getTimeFrames(){
  var ss = SpreadsheetApp.getActive();
  var cell = ss.getRange("C1").getValue();
  Logger.log(cell);
  
  var unique = ss.getSheetByName(cell).getRange("M2:M").getValues().flat().filter(onlyUnique)

  console.log(unique)
}
function onlyUnique(value, index, self) {
  return self.indexOf(value) === index;
}

Answer 2

This was really a tough job before ES6 . But now, with a combination of filter() and indexOf() you can easily pull it off.

For Example:

var List = ['One','Two','Two','One','One','Two','One','Three']
const uniqueList = (value,index,self) =>
{return self.indexOf(value) ===index;}
var finalUniqueList =List.filter(unique); 

Answer 3

Try spreading the unique values into an array:

function getTimeFrames() {

  const sheet = SpreadsheetApp.getActive()
  const cell = sheet.getRange(`C1`).getValue()
  
  const values = sheet.getSheetByName(cell)
                      .getRange(`M2:M`)
                      .getValues()
                      .filter(String)
                      .flat()

  const unique = [...new Set(values)]

  Logger.log(unique)

}