I have a 1X100 cell which contains exclusivly 1X24 cells. I need to extract these 100 cells and join them together to form a 100X24 cell, how can this be done?
I have been playing around with the 'cellfun' function and also using for loops to try an perform the operations required but without success. I understand I could just join these cells one by one but would prefer a more efficient approach. Any help would be appreciated.
The cell is generated from raw data using the following:
for i = 1:100
band{i} = prctile(e-data,i);
end
where e_data is a 62X24 double
The second input to prctile can be an array of percentages so your code can be replaced with
band = prctile(e - data, 1:100).';
This will create a 100 x 24 numeric array which is going to be more performant than a cell array.
In general though, if you need to concatenate the contents of multiple cells together, you can use {:} indexing to yield a comma separated list which can then be passed to cat
result = cat(1, band{:});
If I understood your purpose correctly, you need to use iscell() and retrieve what you want subsequently:
R=cellfun(#iscell, YourCell);
Demanded_Cell=YourCell(R);
Related
I have created a function which takes vectors for input variables and returns a cell array for each set of inputs. The final output variable (out) seems to consist of a 2x1 cell containing two 1x5 cells. I have provided a screenshot of this below:
I am just trying to figure out how to flatten the cell array (out) to be a 2x5 cell array.
One way to achieve that would be -
vertcat(cell_array1{:})
If your cell has unequal number of elements in each row , maybe this might work better
vector=[cell_array{:}]
I am a beginner in Matlab and have not been able to find an answer to my question so far. Your help will definitely be very much appreciated.
I have 70 matrices (100x100), named SUBJ_1, SUBJ_2 etc. I would like to create a loop so that I would calculate some metrics (i.e. max and min values) for each matrix, and save the output in a 70x2 result matrix (where each row would correspond to the consecutively named SUBJ_ matrix).
I am struggling with both stages - how to use the names of individual variables in a 'for' loop and how to properly save individual outputs in a combined array.
Many thanks and all the best!
Don't use such variable names, create a big cell array named SUBJ and put each Matrix in it.
r=zeros(numel(SUBJ),2)
for idx=1:numel(SUBJ)
r(idx,1)=min(min(SUBJ{idx}))
r(idx,2)=max(max(SUBJ{idx}))
end
min and max are called twice because first call creates maximum among rows, second call among columns.
Even though this is in principle possible in Matlab, I would not recommend it: too slow and cumbersome to implement.
You could instead use a 3-D matrix (100x100x70) SUBJ which would contain all the SUBJ_1 etc. in one matrix. This would allow you to calculate min/max etc. with just one line of code. Matlab will take care of the loops internally:
OUTPUT(:,1) = min(min(SUBJ,[],1)[],2);
OUTPUT(:,2) = max(max(SUBJ,[],1)[],2);
Like this, OUTPUT(1,1) contains min(min(SUBJ(:,:,1))) and so on...
As to how to use the names of individual variables in a 'for' loop, here gives an example:
SUBJ = [];
for idx = 1:70
term = eval(['SUBJ_',num2str(idx)]);
SUBJ = [SUBJ; max(max(term)),min(min(term))];
end
I have imported a lot of data from an excel spreadsheet so that I have a 1x27 matrix.
I have imported data from excel using this
filename = 'for_matlab.xlsx';
sheet = 27;
xlRange = 'A1:G6';
all_data = {};
for i=1:sheet,
all_data{i} = xlsread(filename, i, xlRange);
end
However each element of this all_data matrix (which is 1x27) contains my data but I'm having trouble accessing individual elements.
i.e.
all_data{1}
Will give me the entire matrix but I need to perform multiplications on individual elements of this data
also
all_data(1)
just gives '5x6 double', i.e. the matrix dimensions.
Does anybody know how I can divide all elements of each row by the third element in each row and do this for all of my 'sub-matrices' (for want of a better word)
Assuming that all_data is a cell array and that each cell contains a matrix (with at least three columns):
result = cellfun(#(x) bsxfun(#rdivide, x, x(:,3)), all_data, 'uniformoutput', 0);
You are mixing terminology in matlab. what you have is 1x27 CELLS each of them containing a matrix.
If you access all_data{1} it will give you the whole matrix stored in the first cell.
If you want to access the elemets of that matrix then you need to do: all_data{1}(2,4). This example access the 2,4 element of the matrix in the first cell.
Definitely Luis Mendo has solved you problem, but be aware of the differences of Cells and matrixes in Matlab!
Okay I have found the answer now.
Basically you have to use both types of brackets because the data types are different
i.e. all_data{1}(1:4) or something like that anyway.
Cheers
I have a cell array of 447*1 Dimensions. The cell array has 2Dimensional arrays of different dimensions of type double. I want to check a particular value in that cell array compare and on that basis store it in a new Matrix.
So for example my my starting cell array is Y{447*1} . My first cell contains an array of
5*10 and second array contains data of 22*10 . I want to evaluate the second column
of this array and then store it in a new Matrix.
I did this for one set of data and the code looks something like this.
A = [y{2,1}(1:20,2),y{4,1}(1:20,2),y{6,1}(1:20,2),y{8,1}(1:20,2),...
y{10,1}(1:20,2),y{12,1}(1:20,2),y{14,1}(1:20,2),y{16,1}(1:20,2),...
y{18,1}(1:20,2),y{20,1}(1:20,2),y{22,1}(1:20,2),y{24,1}(1:20,2),...
y{26,1}(1:20,2),y{28,1}(1:20,2),y{30,1}(1:20,2)];
But I want to automate the thing. Please help how this can be done.
Something along the lines of:
Temp = cellfun(#(x) x(1:20,2),Y(1:2:end,1), 'UniformOutput', false);
A = cat(2,Temp{:});
Should work if I am reading your question right - it should replicate your example anyway.
You can then change the dimensions of the #(x) function x(1:20,2) to take out different values from your cell array, and use different cell indexing for Y(:,1) to pick different parts of Y.
If I have a Matlab CELL line of string characters separated by a comma like:
12/28/2012,00:00:01,0.99458,1,10518,0.99458,0.99483,0,0,0,0,-,-,-,b,-,C
How do I separate each one into its own column within a matrix? What is the most efficient way of doing this?
Can this be done?
Thanks
UPDATE: Just realized this question duplicates how-to-convert-comma-separated-string-to-cell-array-of-strings-in-matlab and that my answer duplicates the answer provided by #Jonas. I'm flagging it as a duplicate.
Here is the most efficient method I'm aware of:
%# Build your string
Input = '12/28/2012,00:00:01,0.99458,1,10518,0.99458,0.99483,0,0,0,0,-,-,-,b,-,C';
%# Convert to cell array of strings
Output = regexp(Input, '([^,]*)', 'tokens');
Output = cat(2, Output{:});
Some points to note:
1) Note, this will work whether Input is a character array (ie a string) or a cell containing a character array.
2) I've assumed you want the output to be a cell array of strings. Offhand, I can't think of another way of grouping strings of differing length into separate columns using Matlab without building your own custom class.
3) The solution provided by #IlyaKobelevskiy will group the strings into separate rows (not columns) and thus essentially limits you to only a single observation.
Assuming str is your cell line:
str ={'12/28/2012,00:00:01,0.99458,1,10518,0.99458,0.99483,0,0,0,0,-,-,-,b,-,C'};
ind=strfind(str{1},',');
len=diff([0 ind]);
sz=max(len);
A=zeros(length(ind),sz);
prev=1;
for i=1:length(ind)
A(i,1:len(i)-1)=str{1}(prev:(ind(i)-1));
prev=ind(i)+1;
end;
A=char(A);
Not sure if it is the most efficient way, but should work...