Delete days containing less than a specified amount of values

Hello,

I have large datasheets containing dates and values on those dates, like this:

09/02/2018 670

09/02/2018 1093

10/02/2018 8392

...

..

Of course this is a very small example. I am not interested in the values behind each datapoint but rather the amount of data belonging to each date. So for 09/02/2018 this would be an amount of 2. I have figured out how to 'tally' these points with this code:

      Adt = datetime(TimeAD(:,1), 'Format','dd/MM/yyyy');
      [H,E] = discretize(Adt, 'day');
      Tally = accumarray(H, 1);
      assignin('base', 'Result', Result)
      assignin('base', 'Tally', Tally)

How can I delete the date and all the values belonging to this date if the tally values are less than a certain amount? So if I chose a value of 4 datapoints on 09/02/2018, then the 2 would not suffice and should be removed from the datasheet.

Answer 1

[Guillaume]

Note that your

 [H,E] = discretize(Adt, 'day');
 Tally = accumarray(H, 1);

could be written more simply as:

Tally = histcounts(Adt, 'BinMethod', 'day');

The way to get what you want is to indeed use histcounts:

[Tally, ~, bin] = histcounts(Adt, 'BinMethod', 'day');
binstoremove = find(Tally <= 2);  %2 being the threshold at which you want to remove elements
toremove = ismember(bin, binstoremove);
Adt(toremove) = [];

[Debbie Oomen]

Thank you so much!