Select parts of number from a cell of many numbers to put in a variable?

Hi.

I have used

    [num text raw] = xlsread(filename)

to get access to the cells on a bastardised xml/csv type text file. I can read values from cells using

    raw(row,col)

This is fine, however my question is, one of these cells contains the date in format

    20140802

I wish to select parts of the number and assign variables for month(08), day(02), year(2014).

How exactly can I achieve this? I can't seem to find an answer to what seems to be an easy problem, help appreciated!

Answer 1

[Ben11]

The easy way would be:

year = YourDate(1:4)
month = YourDate(5:6)
day = YourDate(7:8)

Then you can convert to digits with str2double for example. Is that what you mean?

[Ross]

This looks like it should work but as usual with my experience of matlab, it gives me errors before I even get to thinking about converting. Should I perhaps str2num my date variable first?

[Ben11]

Hum if you use str2num on your string you will get a double of size (1x1), and then accessing foe instance YourData(1:4) for the year will generate an error. What error message do you get when you run my code above?

[Ross]

The error I get is:

Index exceeds matrix dimensions.
Error in myCode (line 54)
year = date(1:4);

[Ben11]

ok well this error would be expected if 20140802 were of class double, but not if it were a string. Are you sure it is indeed a string?

[Ross]

Ah, thanks Ben! I got it now! I changed my date calling function from

raw(3,14);

to

num(3,14);

then converted to a string and your code worked great, thanks for that! :)

This is so I can use the variables to print out the date on a 2d plot title using:

titleName = (['Graph Plot at', time, 'on', Day, Month, year]);

Now the only problem I have is that the date is printed out like this

Graph Plot at time on
       2013
        08
        06

[Ben11]

Great glad to help!

You can use sprintf to format your title as you like. Eg

title = sprintf('Graph Plot at %d:%d on %d/%d/%d',hours,minutes,day,month,year)

where hours and minutes are up to you of course.

[Ross]

I can't seem to get this to work, I either get invalid format errors or it seems to work and no title is present. My version has a return carriage after every comma, whereas I would like it just as one line.

[Ben11]

When you say "it seems to work but no title is present" do you use something like this:

TitleString = sprintf('Graph Plot at %d:%d on %d/%d/%d',hours,minutes,day,month,year);

... add code for your plot

title(TitleString)

if you don't see any title it might be because matlab does not put it at the right place?

[Ross]

I tried this (minus hours and minutes)

titleName = sprintf('Graph Plot at on %d/%d/%d',day,month,year)
title(titleName)

No error but the title is just blank. Also, I can't seem to add my 'time' variable with this syntax without it just printing time, whereas when I use:

titleName = (['Graph Plot at', time, 'on', Day, Month, year]);
title(titleName)

It does print the value of the variables except it's as though it's carriage returning after each comma. As mentioned, it is coming out like this:

Graph Plot at
     time
      on
      06
      08
     2013

Wheras I would like it to display on the title as

Graph Plot at (time) on (day)(month)(year)

So close, it's probably a simple thing I'm missing or some title formatting option I haven't encountered.

Answer 2

[Azzi Abdelmalek]

a=20140802
b=datevec(datenum(num2str(a),'yyyymmdd'))

b(1)  % is the year
b(2)  % the month
b(3)  % the day

[Ross]

This didn't work and gave me all sorts of errors unfortunately.

Undefined function 'fix' for input arguments of type 'cell'.

Error in num2str (line 66)
      if ~isempty(x) && isequalwithequalnans(x, fix(x))

Error in filename (line 44)
b=datevec(datenum(num2str(date),'yyyymmdd'))

[Azzi Abdelmalek]

Ross, If you run my code with my data, there are no errors. You just need to use the same class of data then mine, or use this one

a={20140802  20140803} 
b=cellfun(@num2str,a,'un',0)  % convert from numeric to string
c=datevec(cellfun(@(x) datenum(x,'yyyymmdd'),b))

[Ross]

Hi, thanks for replying.

This code sorta works, I get the date parsed but it displays in column format, so my date cell displays like so:

2013
  8
  6
  0
  0
  0

Original data, ie variable b looks like '20130806'. How to get it so I have variables such as:

Year = 2013
Month = 08
Day = 06

I don't quite understand this line in your code:

c=datevec(cellfun(@(x) datenum(x,'yyyymmdd'),b))

EDIT: Actually when I look at 'c' in the main window it displays as:

2013 8 6 0 0 0

This is for displaying in a title of a 2d plot. The title on the plot displays in columns and has the 3 unnecessary zero's which is why I was looking to separate the year, month and day to use easier with the title code which I have as:

titleName = (['Graph Plot at', time, 'on', day, month, year]);