Help with a Line chart to visualize the growth of my portfolio

[Luca Pizzolato]

Hello, I am not a developer so unfortunately I can't code scripts.

I have an issue with this line of code that I have found on youtube, potentially it could solve my problem but it doesn't work.

I have 1 tab that shows the earning of my portfolio everytime I update it, so I would like to visualize how is doing with a simple line chart that update everytime I update the page.

What I have found is this line of code:

/*

EVENT FUNCTION

Each time the spreadsheet is opened or refreshed

append a new entry

on the Trend sheet

for the sum of the TotalGain/Loss column

from the Portfolio sheet.

*/

function onOpen() {

  var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();

  var portfolioSheet = spreadsheet.getSheetByName('portfolio');

  var rng = portfolioSheet.getRange(7,15,portfolioSheet.getLastRow());

  var values = rng.getValues()

  var total = 0

  for (var i = 0; i < values.length; i++) {

    if (parseFloat(values[i]) > 0) {

      total = total + parseFloat(values[i]);

    }

  }

  

  var localDateTime = new Date()

  var trendSheet = spreadsheet.getSheetByName('Trend');

    trendSheet.appendRow([localDateTime, total]);

}

The numbers 7 to 15 are the return for every stocks I have. The most common error I receive when I update is that it doesn't calculate the fact that I have losses so it does the sum. sometimes I receive a value equal to 0 which is impossible.

I have another cell that return the sum of those values, I would only like to take that number but it doesn't work if I change it here var rng = portfolioSheet.getRange(7,15,portfolioSheet.getLastRow());

Maybe someone can help me. Thanks a lot