I've been told what I'm hoping to do is called 'spline interpolation'.
I've imported monthly youtube channel viewership figures from google API. And I've layed out the dates and views in a horizontal range. On the right I want to be able to pick a date and show a rough viewership figure that's close to the actual viewership figure, so interpolating as if it were on a curved line of best fit with multiple peaks and trophs.
The reason is to create a youtube channel directory with monthly actual viewership figure and % monthly difference on a curved line of best fit since the channels beginning.
Here's the google spreadsheet example anyone can edit:
https://docs.google.com/spreadsheets/d/1ZzC04y5DXJG9334a9za_vgTu7NI1aIh0C87IXsKJt3Q/edit?usp=sharing
And I need it to work with blank/unknown cells. So using a formula that doesn't treat empty cells as an error, or fills them in based on the average of known figures to both sides in a series.
This is the closest answer I've found so far, but I can't get the formula/code to work:
Best Answer
You are analysing data for 'line of best fit' where there are missing elements in the data range. How to interpolate data in a range in Google Sheets has provided a custom function with which to identify the missing elements.
The following formula attempts to provide a method by which the interpolated data can be calculated.
The formula is a combination of of
vlookup
to return actual data values and the custom functionmyInterpolation()
to return values for missing data elements.The data is based on views for channel "Patrik Baboumian"
'=iferror(vlookup(C3,$A$3:$B$26,2,false),round(myInterpolation($A$3:$A$26, $B$3:$B$26, C3),0))
Actual Data and Interpolated data