retime timetable based on custom definition of year

Hi and thanks in advance.

I have a timetable that i want to retime to yearly data and find the counts of variable 'cat'. THe issue is that unlike the usualy definition of 'year' in Matlab 'retime' (which is Jan 1 to Dec 31), I want to define my year as starting on July 1 in the current year and ending on Jun 30 in the next year and use this definition to retime my timetable.

One of the method that i can think of is offsetting my data by adding months(5) to the original time and then retimeing it 'yearly' and manually labeling my graphs x-axis (this can be bit tedious for me). Im hoping that there is a better way around this.

highly appreciate if someone can help.

Answer 1

[Hassaan]

% Load the .mat file containing the timetable
loadedData = load('matlab.mat');  % Replace with your actual .mat file path

% List the variables in the loaded data
vars = whos('-file', 'matlab.mat');

% Display the variable names
disp({vars.name});

tt = loadedData.a8data_org1;  % Replace with your actual timetable variable name from the .mat file

% Apply the function to calculate the fiscal year for each time entry in the timetable
% Assuming 'time' is the name of the datetime variable in 'tt'
tt.FiscalYear = arrayfun(@(d) fiscalYear(d), tt.time);

% Assuming 'cat' is the variable in 'tt' that contains the category data
% Create a combined variable 'YearCat' as a string for fiscal year and category
tt.YearCat = strcat(string(tt.FiscalYear), "_", string(tt.cat));

% Convert 'YearCat' to unique numeric indices
[categories, ~, idx] = unique(tt.YearCat); 

% Count occurrences of each unique category
counts = accumarray(idx, 1);

% Plot the counts
figure;
bar(counts);
set(gca, 'xticklabel', categories); % Set the x-axis labels to the categories
xlabel('Fiscal Year_Category');
ylabel('Count');
title('Counts by Fiscal Year and Category');

% Define the function to determine the fiscal year
function fy = fiscalYear(d)
    if month(d) >= 7
        fy = year(d);
    else
        fy = year(d) - 1;
    end
end

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[Sarvesh]

Thanks Muhammad, this is what i needed. Just made some changes to it and it worked in the way I wanted. Much appreciated

Answer 2

[Steven Lord]

Based on your description I suspect you're calling retime with the second input being 'yearly'. As far as I'm aware there's no option to specify when the 'year' starts for purposes of the newTimeStep input argument's definition of 'yearly'. However, you could call retime with a vector of times (the syntax using the newTimes input argument rather than the newTimeStep input.) It would require you to determine the starting and ending years you need to include in that newTimes vector, but that shouldn't be that difficult.

n = 10;
y = randi([1990, 2030], n, 1);
m = randi(12, n, 1);
d = randi(28, n, 1); % No 29th, 30th, or 31st of any month
randomDatetimes = datetime(y, m, d)

randomDatetimes = 10×1 datetime array
   10-Mar-2006
   20-Feb-1991
   02-Feb-1999
   07-Mar-2029
   19-Jun-2016
   27-Feb-2011
   13-Jun-2012
   16-Dec-2007
   12-Feb-2022
   06-Nov-2025

firstDate = min(randomDatetimes)

firstDate = datetime
   20-Feb-1991

yearOfFirstDate = year(firstDate)

yearOfFirstDate = 1991

if firstDate > datetime(yearOfFirstDate, 7, 1)
    disp("firstDate occurs on or after July 1st, " + yearOfFirstDate + ...
         ". Use datetime(" + yearOfFirstDate + ", 7, 1) as your starting date.")
else
    disp("firstDate occurs before July 1st, " + yearOfFirstDate + ...
         ". Use datetime(" + (yearOfFirstDate-1) + ", 7, 1) as your starting date.")    
end

firstDate occurs before July 1st, 1991. Use datetime(1990, 7, 1) as your starting date.

sampleVector = firstDate + calyears(0:5)

sampleVector = 1×6 datetime array
   20-Feb-1991   20-Feb-1992   20-Feb-1993   20-Feb-1994   20-Feb-1995   20-Feb-1996