How to add offset'ed individual fields in a google sheet - google-sheets

Question

I am working on adding the time I spend on my habits using google sheets. If you look at this example sheet, I am keeping my individual habits in columns 3-8 (see the offsets on the first row).
To add the food related habits times (columns 5 and 6), I can use the range in offset function (see formulae in D17 below "Food").
The question is: how do I add the numbers for exercise and sleep (column offsets 4, 7, and 8)? The number of columns here could be 2, 3, or more! And they might not be consecutive.
Thanks for any pointers.

Answer 1

To sum entries of the rows whose columns are in the given array, I would use
=SUMPRODUCT(COUNTIF({5,8,9},COLUMN(D3:J3))*(D3:J3))
This is the formula for E18 in your spreasheet.

Answer 2

Since the columns might not be consecutive and there can be a variable number of them, I think it is appropriate to use an Apps Script custom function, and use the spread syntax to account for the variable number of columns.
Just open the script bound to your file, copy this function and save the project:
function HABIT_TOTALS(...habitIndexes) {
const sheet = SpreadsheetApp.getActiveSheet();
const headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0];
let output = [];
for (let dayIndex = 0; dayIndex < 7; dayIndex++) {
let dayValue = 0;
habitIndexes.forEach(habitIndex => {
const columnIndex = headers.indexOf(habitIndex) + 1;
const dailyHabitValue = sheet.getRange(3, columnIndex).getValue();
const dayHabitValue = sheet.getRange(4 + dayIndex, columnIndex).getValue();
dayValue = Number(dayValue) + Number(dailyHabitValue) + Number(dayHabitValue);
});
output.push([dayValue]);
}
return output;
}
Notes:
This function can be used as any in-built formula from Sheets (e.g. =HABIT_TOTALS(4,7,8)).
This function gets, as arguments, the indexes of the habits to retrieve (in this case 4, 7, 8), to be found on the first row in the sheet.
It loops through all days of the week (dayIndex), returning the total amount for each day. Because of this, there's no need to drag the formula down.
For each day, it finds the column index based on the habit index provided as an argument, and adds the values for Daily and for the current day to the total value for the day.
After retrieving the total amount for the day, this value is pushed to output, the value returned by this function.
This function could be used for the Food habits, just changing the arguments: =HABIT_TOTALS(5,6), or for any other combination.
Reference:
Custom Functions in Google Sheets
Spread syntax (...)

Answer 3

For the calculation concerning food you can try in cell D18
=sum(filter(filter($D$3:$I$11, regexmatch($C$3:$C$11, "Daily|"&text($C18, "ddd"))), regexmatch($D$1:$I$1&"", "5|6")))
and fill down.
The numbers at the end refer to the colum numbers you have in row 1. So in E18 (Sleep and excercise) you would have
=sum(filter(filter($D$3:$I$11, regexmatch($C$3:$C$11, "Daily|"&text($C18, "ddd"))), regexmatch($D$1:$I$1&"", "4|7|8")))
Of course, it is also possible to write the last part in a cell and then refer to that cell. That would mean you can enter in E18
=sum(filter(filter($D$3:$I$11, regexmatch($C$3:$C$11, "Daily|"&text($C18, "ddd"))), regexmatch($D$1:$I$1&"", D$17)))
and fill down AND to the right.
See if that helps?