I need to ingest a CDF (common data format) file into MATLAB. I have used the [cdfread][1] command for this purpose. An image of my output is attached below:
When I open data_import, columns 4 and 5 are in a particular 3 x 1 format (as shown in data_import(1,4)).
My question is: Is there a simple way to extract the data for each cell in column 4, such that for the 2nd row in data_import(1,4), it gets inserted as a new column (i.e. column 5) in the original data (data_import)? Similarly, 3rd row in data_import(1,4) should be inserted as a new column (column 6) in the original data (data_import). This procedure should also be repeated in the original Column 5 data which also has a similar 3 x 1 structure within each cell.
I hope I'm not being too vague in what I am describing, but I'm really not sure what I'm supposed to do regarding the commands to call for the operation. Thank you in advance.
Your desired final output has columns which are made up of these cells converted from 3 x 1 arrays to 1 x 3 cell arrays and then concatenated for each row. It's easier to do the concatenation first with the elements the "wrong way round" and then transpose the final result:
data_import = [data_import(:,1:3) num2cell([data_import{:,4}; data_import{:,5}]') data_import(:,6:end)];
Related
I have a table (L-arrival) of 279 rows and 252 columns. Only the first column has values while others are just NaN. The cells in the first column have multiple values (i.e. some have 1, some have 4 number of values). First of all, I am trying to select a single maximum value from each cell of the first column so that I can have a column of a single value for each cell only. Then I want to do this in a loop so that for every new value that I get, they are sorted and only the maximum values are chosen. Finally, I want to make a collection of these values obtained from multiple runs for each cell. Can anyone suggest to me how it can be approached in MatLab?I tried using the following code but didn't work well.
for b=1:279
m = numel(cell2mat(L_arrival(b,1)));
g(b)=mat2cell([cell2mat(g(b)); cell(L_arrival(b,1))]',[1 2]);
end
I have 40 variables. The 40 variables names are in a cell array (40 x 1).
Each variable will have a matrix. The matrix is of type of double and will be size 5000 x 150. It will also have a vector of size 1 x 150 & one last vector 1 x 4.
Initially I was going to dynamically name each struct with its variable name in the cell array. So would look like something like below (assuming variable name is ABC),
ABC.dataMatrix
ABC.dataVec
ABC.summaryData
All the variables would be saved to a directory.
However I've read using eval isn't a very good idea so guessing my idea isn't the best way to go about this problem. What would be the best way to go about this problem?
You can either use struct arrays with dynamic field names, as #Shai and #RobertStettler suggest.
However, another option is a table. This might be more appealing if you want to see your data in one big matrix, and you can give each table row the name of your variables too! Note that the rows in a table would then be what you call your variables, but MATLAB calls the table columns its variables.
Also note that using a table can be more difficult than using struct or cell arrays, but if you know how to use them, you can handle a table too.
An example:
% create dummy data
rowNames = {'a';'b';'c'};
M = {ones(3); zeros(3); nan(3)}; % a cell, one element per item in rowNames
V = [1 2; 3 4; 5 6]; % a matrix of vectors, each row containing a vector for every item in rowNames
% create a table
T = table(M,V,'RowNames',rowNames); % this is where your variable names could go
Now, to access data you could use (some examples):
T(2,:) or T('b',:), return a table for all data on the 'b' row.
T(:,2) or T(:,'V'), return a table of variable V for all rows.
T.V or T{:,2} or T{:,'V'} or T.(2), return matrix V for all rows. This syntax is similar to accessing a (dynamic) field name of a struct.
T{3,1} or T{'c',1} or T.M('c'), return cell M for row 'c'. This syntax is similar to accessing a cell, but with more advanced possibilities, i.e. the ability to access the table via row or variable names.
T{3,1}{:} or T{'c',1}{:} or T.M{'c'}, return cell contents M for row 'c'.
And even more complex: T('a',:).M{:} is a complex way of accessing the cell content of M for row 'a', which can be done with T{1,1}{:} or T.M{'a'} or T{'a','M'}{:} or T.M{1} as well.
In your case you would en up with a 40x3 table, with every row what you call a variable and the first column the matrices (in cell arrays), and the last two columns the vectors (as well in cell arrays or as a 40xm double, m being the length of your vector).
I'm new to MATLAB. I have two values x and y. Both of them contain values with unknown accuracy. The problem: How could I display them both in one row with 2 digits after comma? Like:
x<tabulation or stack of spaces>y<then goes new line>
Example
RAW data
0,324352 0,75234
1,563 3,4556
Expected output
0,34 0,75
1,56 3,45
Upd: for one value it works well
disp('x=' num2str(x,3));
Purpose is: display TWO values on one row with the new line symbol
The answer is:
disp(num2str([x y],3));
The 3 value means - max.quanity of symbols after comma including it(am I wrong? just thoughts)
Another Idea:
Somehow represent X and Y as array values and then display them.
X =
4 3
8 3
I want to extract the element in each row of X and do some operation on each of them separably (4,3) and (8,3). however the size of may be different based on some parameters in my code, so I want general formula to do such thing,
How I can use the for loop for solving this issue ?
This link shows how to extract specific lines (or columns) from a matrix http://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html
All you have to do is write a loop on an index ii to go through every line.
for ii=1:size(X,1)
a=myfun(X(ii,:));
end
I am currently working on a project in Matlab where I have a cell array of cell arrays. The first cell array is 464 columns long and 1 row deep. Each of these cells is another cell array that is 96 columns and 365 rows. I need to be able to get the mean of the 96 columns for each of the 464 arrays and place each of the 464 arrays on a different row in a new array called mean. I have tried to write code to just do one column as follow:
mean = Homes{1,1}(1:)
But I when ever I try to run this code I got the follow error:
mean = Homes{1,1}(1:)
|
Error: Unbalanced or unexpected parenthesis or bracket.
Basically my final array name mean needs to be 96 columns by 464 rows. I am stuck and could really use your help.
Thank you.
I suggest you to try the following code on a smaller matrix. See if it gives you the desired results.
a=cell(1,4); %for you it will be a=cell(1,464)
for i=1:4
a{i}=randi(10,[5 10]); %for you it will be a{i}=randi(10,[365 96]);
end
a1=cell2mat(a); %just concatenating
a1=mean(a1); %getting the mean for each column. in your case, you should get the mean for 96*464
a2=reshape(a1,[10 4]); %now what reshape does it it takes first 10 elements and arranges it into first column.
%Therefore, since I finally want a 4x10 matrix (in your case 464x96), i.e. mean of 10 elements in first cell array on first row and so on...
%Thus, 1st 10 elements should go to first column after doing reshape (since you want to keep them together). Therefore, instead of directly making matrix as 4x10, first make it as 10x4 and then take transpose (which is the next step).
a2=a2'; %thus you get a 4x10 matrix.
In your case specifically, the code will be
a=cell(1,464);
for i=1:464
a{i}=randi(10,[365 96]);
end
a1=cell2mat(a);
a1=mean(a1);
a2=reshape(a1,[96 365]);
a2=a2';