I need to sum values that belongs to same week. For example, I have the list x with one column and n rows. Format:
{{2007,1,3},0.2},{2007,1,4},0.1},{2007,1,5},0.14},{2007,1,8},0.}, ... {2014,10,17},-0.2},{2014,10,18},0.2},{2014,10,19},0.2}}.
Dates in list are sorted in the form from Oldest to Newest. Say differently, is there any function like function "Weekendum" in MS Excel that returns the number of week in the year, so i could use function „GatherBy“ that number of week and „Accumulate“ the values.