How to specify date ticks on plot

Hi,

I'm trying to plot the attached csv file, but i am having problems creating a tidy x axis labels. Ideally, I would like a label to read: 2000, 2004, 2008, 2012, 2016, 2020, starting on the earliest date for each year. However, despite trying to set my xtick using a string converted through datenum, I can't figure out how to achieve this result. My code, with the neatest labels I can manage, is attached, but this doesn't produce my desired labels. Any suggestions?

%plots the price of copper from https://www.macrotrends.net/1476/copper-prices-historical-chart-data
close all;

fid = fopen('copper-prices-historical-chart-data.csv');
 if fid>0
     % note how we skip the header lines and use the delimiter
     data = textscan(fid,'%s %f','Delimiter',',','HeaderLines',16);
     % close the file
     fclose(fid);

     startlim = datenum('07-Jan-2000');
     endlim = datenum('31-Mar-2020');
     
     date = data{1,1};
     dn = datenum(date, 'yyyy-mm-dd');
     
     price = data{1,2};
     
     dateplot = dn(10141:end);
     priceplot = price(10141:end);
     
     plot(dateplot,priceplot);
    xlim([startlim, endlim]);
    xticks=get(gca,'xtick');
    xtickangle(45);
    set(gca,'xticklabel',cellstr(datestr(xticks))')
 end

Thanks in advance.

Answer 1

[Star Strider]

Try this:

TCu = readtable('copper-prices-historical-chart-data.csv');

startlim = '07-Jan-2000';
endlim = '31-Mar-2020';
GetRows = isbetween(TCu.date, startlim, endlim);

figure
plot(TCu.date(GetRows), TCu.value(GetRows))
grid
xlim([datetime('01-Jan-2000')  datetime('31-Dec-2020')])
xtickformat('yyyy')
xticks(datetime('01-Jan-2000') : calyears(4) : datetime('31-Dec-2020'))

producing:

The datetime functions require R2014b or later.

[Ted Baker]

Thank you very much for that example, Star Strider. It works perfectly.

[Star Strider]

As always, my pleasure!

Answer 2

[Adam Danz]

Convert your dates to datetime values using datetime().

Then use xtickformat('yyyy') to set the datetime format for the x-tick values.

Here's an example.

[Ted Baker]

Thanks for the reply Adam, but despite looking at the references you provided, I am not able to figure out how to convert the date values using datetime. Are these converted values the ones I want to use to make my plot?

[Adam Danz]

You would use this syntax t = datetime(date,'InputFormat',infmt) (see link) on your date variable.

If you provide an example of the date variable I can be more specific.

[Ravi]

I have data which is time dependent but time data is not avaialble. I needed to plot this data with time so I created time loop with size matching up with the data size. I am able to get the plot but now I need to put in my desired time ticks on time axis. How can I do this ?

[Adam Danz]

Is your time vector in datetime format? If not, convert it to datetime format and use that vector for your x-variable when plotting so the ticks are in datetime format.