How to save data in multiple sheets with xlswrite?

Hi, I would like to save data from a cell with xlswrite into multiple sheets of the workbook.

In sheet 1 I would like to save the data from year one, in sheet 2 data from year two, and so on.

My code looks like this:

for f=1:length(duniqyear)
    empty=zeros(1,length(A));
    j=0;
    X=regexprep(Y(f,:),Y(f,:),sprintf('%s$0','Z'))
    Z=strfind(A,X);
    for k=1:length(A)
    indx=find(Z{k});
        if indx==1;
            empty(k)=j+1;
        end
    end
    C=find(empty);
    B=A(C);    
    xlswrite(b,B,f)
end

Where

duniqyear =

          2008
          2009
          2010

It is almost working. I need to find the data that matches the year in duniqyear. The problem is that when using

Z=strfind(A,X);

Z returns values that matches all strings containing '2008' and '2009' and so on. This is not what I want as some strings have '200808042230Z' and '02010KT' Groups. I only want to match the expression with the first Group that has information of the year of the string.

The cell A looks like this:

     ...
    'METAR ESSB 201002282250Z AUTO 07006KT 5000NDV BR OVC001/// 01/01 Q0993 3071//73'
    'METAR ESSB 201002282320Z AUTO 07008KT 2900NDV BR VV002 01/01 Q0992 3071//73'
    'METAR ESSB 201002282350Z AUTO 07008KT 4200NDV BR VV002 01/01 Q0992 3071//73'
     ... and so on

I would like to use strfind with both '2010' and 'Z' to identify the year that the string contains. Is this possible or am I on the wrong track here?

Thank you!

[Guillaume]

It's hard to understand your code, not helped by the fact that none of the variable names have meaning, apart from the empty variable which is a name you should not use (as it's an important matlab function).

I certainly don't understand that line

X=regexprep(Y(f,:),Y(f,:),sprintf('%s$0','Z'))

which looks like a variation on the answer I gave to one of your question but simply prepends 'Z' to the strings. If that's the idea:

 zstrings = regexprep( Y(f, :), '.*', 'Z$0'); 
 %or
 zstrings = cellfun(@(s) ['Z' s], Y(f, :), 'UniformOutput', false);

I would think a regular expression would also help you find your year, but without knowing what's in Y, I can't say for sure.

I would also think you may not even need the loop, but need a better description of the inputs.

[Linus Dock]

Ok sorry for the messy code. Here is my Y:

Y=num2str(duniqyear)
Y =

2008
2009
2010

What I'm trying to do with the code:

X=regexprep(Y(f,:),Y(f,:),sprintf('%s$0','Z'))

Is to prepend the year with 'Z' as you mentioned. Thereafter I would like to find 'Z2008' in A. This is clearly not working, but what I really want to do is to find every word or group of the form: 201002282350Z in A.

Is i possible to combine for example '2009--------Z' where --- is mmddHHMM or is there Another way of doing this?

Thank you for your help!

Answer 1

[Guillaume]

If I understood correctly:

%input:
%A: cell array of char arrays. wants to find the year in there.
%   the year (always 4 digits) is preceded by a space and followed by more digits and a 'Z'
%outputs:
%duniqyear: the unique years encoded in A, numeric vector
%Asplit:  Cell array of input grouped by year, corresponding to duniqyear. Asplit is thus a cell array of cell arrays of char arrays

yearstring = regexp(A, '(?<= )\d{4}(?=\d+Z )', 'match', 'once');  %extract year as string
assert(~any(cellfun(@isempty, yearstring)), 'Failed to find year in some string');
[duniqyear, ~, idx] = unique(str2double(yearstring));   %convert to numeric, get unique values and corresponding index in A
Asplit = accumarray(idx, 1:numel(A), [], @(indices) {A(indices)});   %distribute identical years in destination.

You ought to learn regular expressions as it's extremely useful to find and extract patterns from strings.

[Linus Dock]

This worked out! Awesome! Very nice, now I have my data neatly packaged and separated year-by-year in sheets in excel. Thank you so much!