365 day loop for 59 years

Hi there,

This is a beginner question, I'm very new to MATLAB.

I have 59 years worth of data in one column starting in October. There is 1 data point for every day in the year. I would like to create a loop which produces a graph for the data in every year for each of the 59 years.

Thanks,

SS.

[Mathieu NOE]

hello

maybe you should share the data file to let us help you

[Cris LaPierre]

Don't forget - every 4 years there are 366 days.

[David Hill]

Show us the code you currently have.

[S.S]

Hi there,

Thanks for taking a look at my question. I have attached the data file, which is in excel format.

Kind regards,

SS.

Answer 1

[Cris LaPierre]

Make sure your dates are datetimes. Then you can take advantage of the dates and time functions.

Here's a rought outline.

startY = min(year(data.Var1));
endY = max(year(data.Var1));
for y = startY:endY
    ind = year(data.Var1)==y;
    plot(day(data.Var1(ind),'dayofyear'),data.Var2(ind))
    hold on
end
hold off

[Cris LaPierre]

This solution will work for your data. You just have to load your spreadsheet into MATLAB. I'd use readtable.

data = readtable("data .xlsx",'Sheet','Sheet2')

The variable data is a table data type. See this page on how to access data in a table.

[S.S]

Hi Cris,

Thanks for answering my question. I imported the data from matlab and then converted the date formats from excel to matlab so my codes reads like this at the beggining:

X = data(:,1);

Y = data(:,2);

t = datetime(X,'ConvertFrom','excel')

So, now I have to columns one t with the dates that I would like to use as the X axis and column two (Y) which I'd like to plot on the Y axis

I'm not a bit unsure, how to translate these into the code above. Sorry I'm a big biggner here!

Kind regards,

SS.

[Cris LaPierre]

Just combine the two. That's all you need. The readtable function will automatically handle the date for you. This was run in R2020b.

data = readtable("SSdata .xlsx",'Sheet','Sheet2') % I saved your file with this name

data = 21549x2 table
       Var1        Var2
    ___________    ____

    01-Oct-1960    8.07
    02-Oct-1960    59.8
    03-Oct-1960    53.2
    04-Oct-1960    23.3
    05-Oct-1960    19.1
    06-Oct-1960    15.4
    07-Oct-1960    11.6
    08-Oct-1960    11.6
    09-Oct-1960    9.46
    10-Oct-1960    8.81
    11-Oct-1960    7.76
    12-Oct-1960    13.3
    13-Oct-1960    8.04
    14-Oct-1960    8.75
    15-Oct-1960    6.88
    16-Oct-1960    6.23

startY = min(year(data.Var1));
endY = max(year(data.Var1));
for y = startY:endY
    ind = year(data.Var1)==y;
    plot(day(data.Var1(ind),'dayofyear'),data.Var2(ind))
    hold on
end
hold off