How can I make a plot with the date and time on the x-axis?

I have imported some data into Matlap. One of the vectors is date and time (ex 19.12.2013 11:56:22). Matlab have made all date formatted cells into Matlab serial date number format. How can I plot my sound power vector aginst the date-time vector? I would like the date-time on the x-axis(not the date number) and the sound power on the y-axis. I have included a small file with some of my data.

Answer 1

[Azzi Abdelmalek]

[~,~,v]=xlsread('data.xlsx')
v=v(2:end,:);
x=datenum(v(:,1),'dd/mm/yyyy HH:MM:SS')
y=cell2mat(v(:,2))
[idx,idx]=sortrows([x,y])
plot(x(idx),y(idx))
xticks=get(gca,'Xtick')
set(gca,'xticklabel',datestr(xticks,'dd/mm/yyyy HH:MM:SS'))

[Henriette]

Hi Azzi

I get this: Error using datenum (line 181) DATENUM failed.

Caused by: Error using dtstr2dtnummx Failed on converting date string to date number.

Is it because I do not have the toolbox with dtstr2dtnummx? When I try the help, it do not know dtstr2dtnummx.

[Azzi Abdelmalek]

You don't need any toolbox

Have you copied and pasted the code?

[Henriette]

Yes I copied and pasted the code, and have det data in the folder where I am working.

[Henriette]

I made a m-file, and the erro has change a littel:

Error using datenum (line 179) DATENUM failed.

Error in date_v1 (line 3) x=datenum(v(:,1),'dd/mm/yyyy HH:MM:SS')

Caused by: Error using dtstr2dtnummx Failed on converting date string to date number.

I can see the improtet data is okay (v).

[Azzi Abdelmalek]

I don't know what is your problem, because it 's working with me

[Henriette]

If I delete 'dd/mm/yyyy HH:MM:SS' in the line

x=datenum(v(:,1),'dd/mm/yyyy HH:MM:SS')

I will get this figure(see attached). But the dates are not correct. non of my data is from 2014.

[Azzi Abdelmalek]

Why delete 'dd/mm/yyyy HH:MM:SS' ?

[Henriette]

I am not so experienced in Matlab, so sometimes I just change things to see if it works, and if I delete ‘dd/mm/yyyy HH:MM:SS’ it gives me a vector with numbers. But the end figure is not correct.