DataGrid Delete Rows

I have some JSON data I am pulling into Domo via a connector however when I Parse the data I end up with a table which has rows with varying numbers of coloumns and therefore wont save into a dataset.

One option I am looking at is to just delete the rows I dont need and end up with one relevant row of the data Im after, but how do I delete Rows.  I have tried different varients of

datagrid.removerow(1);

Datagrid.Rows.Remove(1); 

eg

but nothing seems to work, or is there a was to delete the data before Parsing it (which I have to do twice as everything is a suset of 'data')

var jsonRes = JSON.parse(res);
datagrid.magicParseJSON(jsonRes.data);