excel averageif function in matlab

    for cata = 1:281
       mydata = mean(cellfun(@(x) x(cata,2), thecells));
 data2 = cell2mat(num2cell(mydata));
       plot(cata,data2)
    end

mydata is 5000*2 double look like

time    data  
1  225.42968
1  453.4097824
1  254.1819706
2  164.3800456
2  411.2133781
2  266.0093299
2  399.3169552
3       155.2650000
4       322.7854587
4       366.5487525

i try many methods but cannot create a loop same as averageif function in excel. my prof tell me to put nan for numbers to create same size for each time. But I am wondering another ways of the averageif function in excel.

Answer 1

[Star Strider]

I am not certain what structure your original data are.

Try this:

C = {1  225.42968
     1  453.4097824
     1  254.1819706
     2  164.3800456
     2  411.2133781
     2  266.0093299
     2  399.3169552
     3   155.2650000
     4   322.7854587
     4   366.5487525};

M = cell2mat(C);
Out = accumarray(M(:,1), M(:,2), [], @mean);

[Kuang-Yu WANG]

thanks very much!!

[Star Strider]

As always, my pleasure!

Answer 2

[Steven Lord]

If you're using release R2018a and your data is stored as a table, use groupsummary.

time = [1; 1; 1; 2; 2; 2; 2; 3; 4; 4];
data = [225.42968;
        453.4097824;
        254.1819706;
        164.3800456;
        411.2133781;
        266.0093299;
        399.3169552;
        155.2650000;
        322.7854587;
        366.5487525];
T = table(time, data)
groupsummary(T, 'time', 'mean')

Or you could use splitapply (since your times are already group numbers; if they weren't a vector of positive integer values you would need to use findgroups first.)

meantime = splitapply(@mean, data, time)