MATLAB: Select data from an existing dataset based on the weekday

select rows based on weekdayselect specific data

Hi,

I have a matrix with 18 columns and over 100'000 rows and in each rows there are stored different characteristic for a specific data. In column 6 is the date in this form:

for example 730853 for the 02-Jan-2001

Now I would like to create a new matrix that consists only if those rows where the date refers to a Wednesday, is that possible?

Best Answer

Example 
d1=730853
dates=datestr(d1:d1+100,'ddd-mm-yyyy')
M=[cellstr(dates) num2cell((1:101)')]
M=M(ismember(dates(:,1:3),'Wed','rows'),:)

Related Solutions

MATLAB: Weekday function odd results

That doesn't do what you think it does.

>> datestr(19790531)
ans =
18-Aug-4184

If you intended for that number to refer to May 31, 1979:

>> D = datetime(19790531, 'ConvertFrom', 'yyyymmdd')
D = 
  datetime
   31-May-1979 00:00:00
>> [DayNumber, DayName] = weekday(D)
DayNumber =
     5
DayName =
Thu

MATLAB: Assign categorical value for weekday variables

Since you have a timetable you can use the isweekend function to get true and false values (which you could convert to categorical or leave as logical) from the RowTimes property.

% Make some sample data
T = datetime('today');
thisWeek = T + days(0:6);
% Process each day
for whichDay = 1:numel(thisWeek)
    D = thisWeek(whichDay);
    if isweekend(D)
        fprintf("%s is not a weekday.\n", D)
    else
        fprintf("%s is a weekday.\n", D);
    end
end

If you wanted to get a categorical array, consider calling categorical on the output of day with the 'dayofweek' input.

Best Answer

Related Solutions

MATLAB: Weekday function odd results

MATLAB: Assign categorical value for weekday variables

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