How can I optimize my code using batch operations? - google-apps-script

Question

I want to perform a basic multiplication on a range of values in my spreadsheet, and then divide those values by a range of values from a column, note that my range is 8 columns long and my division range is one column long.
I have this code:
function multiply() {
var doc = SpreadsheetApp.openById(SCRIPT_PROP.getProperty("1iXQxyL3URe1X1FgbZ76mEFAxLnxegyDzXOMF6WQ5Yqs"));
var sheet = doc.getSheetByName("json");
var sheet2 = doc.getSheetByName("tabla de frecuencias");
var sheet3 = doc.getSheetByName("Template");
var range = sheet2.getDataRange();
var numRows = range.getNumRows();
var numCols = range.getNumColumns()-1; //This will get the division values which are located in the last column
var targ = sheet2.getLastColumn();
for (var i = 2; i <= numRows; i++) {
for (var j = 2; j <= numCols; j++) {
var A = range.getCell(i,j).getValue();
var value = A;
for (var v = 1; v <= numRows; v++) {
var T = range.getCell(v,targ).getValue();
range.getCell(i,j).setValue(value*100/T);
}
}
}
}
It's very slow, it reads and writes on each cell from a sheet where I have numeric values ready to be multiplied by 100 and divided by a value located in a single column, this value is different for each row.
My script gets the job done extremly slowly, batch operations appear promising, if that's not the best solution, I will accept any other alternate solution regardless of the question title.

Answer 1

I think this is what your looking for.
function multiply()
{
var ss=SpreadsheetApp.getActive();
var sh=ss.getSheetByName("Sheet60");
var rg=sh.getDataRange();
var dataA=rg.getValues();
for(var i=1;i<dataA.length;i++)
{
for(var j=1;j<dataA[0].length-1;j++)
{
var value=dataA[i][j];
for (var v=1;v<dataA.length;v++)
{
var T=dataA[v][dataA[0].length-1];//the value in the last column on this row
Logger.log('v=%s dataA[%s][%s]=%s',v,i,j,dataA[i][j]);
dataA[i][j]=value * 100 / T;//This seems wrong because it puts a different value into dataA[i][j] which doesn't change inside this inner loop and so only the last value remains in dataA[i][j]
}
}
}
rg.setValues(dataA);
}
Try to minimize the use of getValue and replace with one getValues to get all values in two dimensional array. Then setValues all at one time at the end of the loop.
Okay made another change. Getting more reasonable results.
I'm beginning to think that you may not actually want the v loop at all. Take a look at this one and look at the Logger. We just write the data once.
function percentages()
{
var ss=SpreadsheetApp.getActive();
var sh=ss.getSheetByName("Sheet60");
var rg=sh.getDataRange();
var dataA=rg.getValues();
for(var i=1;i<dataA.length;i++)
{
for(var j=1;j<dataA[0].length-1;j++)
{
var value=dataA[i][j];
var T=dataA[i][dataA[0].length-1];
dataA[i][j]=value * 100 / T;
Logger.log('dataA[%s][%s]=%s',i,j,dataA[i][j]);
}
}
rg.setValues(dataA);
}
This is the output for this version.