Sorting data from table

Hi, I have a table T (8766x4) columns are - month, day, year and Flow rate (that is 24 years of data - 8766 days). I need to sort flow rate for each year separately and descend flow rate for each year and then plot.

P.S. I am afraid this approach with tables is wrong

Answer 1

[Andrei Bobrov]

T - your table with variables: month, day, year and prutok.

ii = findgroups(T.year);
Prutok = accumarray(ii,T.prutok,[],@(x){sort(x,'descend')});
for jj = 1:numel(Prutok), plot(Prutok{jj}); hold on; end

other variant

Days1 = day(datetime(T{:,{'year','month','day'}}),'dayofyear');
c = findgroups(T.year);
Anew = sort(accumarray([Days1,c],T.prutok,[],[],nan),'descend');
plot(Anew)

(added)

and the best variant by Guillaume and Peter

hold on
varfun(@(x)plot(sort(x,'descend')),T,'GroupingVariable','year','InputVariable','prutok');
hold off

[Guillaume]

Assuming that's what is wanted, this is probably simpler:

varfun(@(col) plot(sort(col, 'descend'), T, 'GroupingVariables', 'year', 'InputVariables', 'prutok')

[Jiri Soucek]

Andrei Bobrov Thanks a lot :)

Answer 2

[Guillaume]

Simple:

sortedtable = sortrows(yourtable, 'year', 'flowrate', {'ascend', 'descend'})  %sort ascending by year, and for identical year, descending by flow rate

where 'year' and 'flowrate' are the variable names of your year and flow rate column respectively.

A table is the right approach.

[Jiri Soucek]

 :( It doesnt work (it says that variable 'year' its class is 'double' and more if it would/will work i need to plot it to get this

I allready manage to plot the values by this method:

r=1994; while r<=2017

    r=r+1;
    Q_rocni2=T.prutok(T.year==r);
    Q_rocni2_sort=sort(Q_rocni2,'descend');    %seřazen průtok za 1 rok

    plot(Q_rocni2_sort,'b'); hold on

but I would like to have values in table/matrix, where rows are flowrates and one column is one year for example. Because I nee to work with values furthemore

Thanks

[Peter Perkins]

I think something like Guillaume's is the right way to go: sort the data by time, then make a plot for each year. From the plot you made, it seems like your original description is not accurate -- it looks to me like you want to plot flow rate by time, overlaying each year.

So: sortrows using year/month/day, then use varfun to make the plots (with hold on/of before and after).