Script to calculate percentage between consecutive cells Google Sheet

Question

I have a list of daily close prices for bitcoin in a column B and am trying to write a script that would put the %change between row i and rowi-1 in the adjacent column C (column A is the date). The calculation needs to start from the last row and go back up to row number 2.

I used the code below and get 2 types of issues:

• my variable "percentageValue" return an array of [null,null,...]
• my final row generates the error message "Exception: The number of rows in the data does not match the number of rows in the range. The data has 1 but the range has 446."

For the logic I tried to work with 2 variable I could divide for the percentage calculation: rangePriceValues (prices at day 2) and rangePricelastValues (values at day 1).

I tried to find similar code online and couldn't find anything close (but am sure there must be one somewhere) I am new to Java and would really appreciate if someone could put me on the right track.

Thanks!!

function PopulateC() 
{
 var sheet1 = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Test__Price"); 
  var rangePrice = sheet1.getRange(2,2,sheet1.getLastRow(),1);  // full list of prices
  var rangePriceValues = rangePrice.getValues(); // value of these prices 
 var secondLastRow = rangePrice.getNumRows()-2; //total number of rows minus one value
  var rangePricelast = sheet1.getRange(2,2,secondLastRow.valueOf() ,1);  // full list of prices minus one
  var rangePricelastValues = rangePricelast.getValues(); //value of the prices at day+2

  var percentage = [];
  var percentageValue = [];
  var rangePercentage = sheet1.getRange(2,3,rangePrice.getNumRows(),1);

  for (i= rangePrice.getNumRows(); 2; i--)
    {
      percentage [i-1] = (rangePriceValues[i]/= rangePricelastValues[i]-1)* 100;
      percentageValue= percentage.valueOf();
 Logger.log(percentageValue) // this is where I see my array with [null, null,....]
      rangePercentage.setValues([percentageValue]);
    }
  }
`



 

Answer 1

Change this: var rangePrice = sheet1.getRange(2,2,sheet1.getLastRow(),1);

to This: var rangePrice = sheet1.getRange(2,2,sheet1.getLastRow()-1,1);

Answer 2

I found a way to solve the problem by writing a simpler code. It works but the calculation is very slow. If anyone has a view on how to optimise the code I would be super grateful, as I am still learning. Thanks Cooper for the suggestions!

    function SimplePerc() {
    var sheet1 = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Test_Bitcoin_Price");
  var rangePrice = sheet1.getRange(2,2,445,1);  
  var priceValue = rangePrice.getValues(); 


 for (var i=sheet1.getLastRow() ; 2; i--)
{
 var numerator = sheet1.getRange(i,2).getValue();
 var denominator = sheet1.getRange(i+1,2).getValue();
 var percentagecalc = (numerator /= denominator);
 var percentageclean = (percentagecalc -1)*100;
 sheet1.getRange(i,3).setValue(percentageclean);
  }
};