How can I get MATLAB to plot a date on the x-axis?

I have a dataset with column1 = date and column2 = data. The problem is that my date is in yyyymmdd format. How can I get MATLAB to plot the date correctly in the x-axis?

Thank you in advance! :)

[sixwwwwww]

Do you have ur data in txt file or excel file?

[Sandy]

It's a text file.

Answer 1

[dpb]

First convert the text string date format to Matlab serial dates --

doc datenum

Then plot with that value as the x-axis value and format the dates as desired via

doc datetick

dn=datenum(data(:,1),'yyyymmdd');
plot(dn,data(:,2))
datetick('x','keepticks','keeplimits')

Salt to suit...

[William]

Thank you! This had been driving me nuts, but now works perfectly.

[dpb]

This answer is now out of date...use the new(ish) datetime class instead of datenum

Answer 2

[Sandy]

Hi dpb. I tried it this way, but for some reason it's plotting all my data as one date.

[Sandy]

Nevermind, I got it. I had to convert my number to strings first. Thank you! :)

[dpb]

Oh, didn't think about the first column being integer, granted...just for the record, alternatively, you could separate out the separate fields and use the

datenum(y,m,d,h,mn,s)

form to generate the serial numbers.

Answer 3

[Dainty Daisy Calgas]

Hello, how could I plot a quarterly data with column1, written as Q1:1991 up to Q4:2016, then my column2 is my data., please I really need help, it was in the excel.

[dpb]

Better form would be to create a new question, but it is at least related so I'll consider it here as "close enough"... :)

Problem first is we need to know how the date data are actually stored and imported. Since the date of the original Q, TMW has introduced the datetime class/object and improved graphics routines to be datetime aware so things are different now than then...