Store data in cell arrays

Hello Everyone,

I know the question below is quite stupid but please help as I am not able o find a solution for it. This is a sample array that I have. I want to check the second column of this. The places where I get 1 should be stored together in cell array. As I start scanning the first 4 values get stored in cell array 1 then as the value in second column is 0 I do not store it . Again when I get 1 I should store but in cell array 2. The number of values that I will get is not fixed.

26.81267 1

26.82500 1

26.83733 1

26.86200 1

37.41933 0

37.40700 0

37.39466 0

37.38233 0

27.08400 1

27.07167 1

27.05933 1

27.04700 1

27.02233 1

Answer 1

[the cyclist]

If A is your original array, then

C{1} = A(A(:,2)==1,:);

is a one-element cell array that stores the 9 rows with a zero.

If you only wanted to store the first column, then

C{1} = A(A(:,2)==1,1);

instead.

[Ricky]

actually I want to store them in 2 cell arrays the first 4 elements go in cell array 1 and last 5 elements go in cell array 2

Answer 2

[Andrei Bobrov]

a =[26.81267 1
26.82500 1
26.83733 1
26.86200 1
37.41933 0
37.40700 0
37.39466 0
37.38233 0
27.08400 1
27.07167 1
27.05933 1
27.04700 1
27.02233 1];

l = [true;diff(a(:,2))~=0];
l(l) = a(l,2);
ll = cumsum(l);
out = accumarray(ll(a(:,2)>0),a(a(:,2)>0,1),[],@(x){x});

OR

l = [true;diff(a(:,2))~=0];
d = diff([find(l);size(a,1)+1]);
out = mat2cell(a(a(:,2)>0,1),d(a(l,2)>0),1);

Answer 3

[Azzi Abdelmalek]

i2=[1 1 0 0 1 1 1 1 0 0 1 1 0 0 0 1 1 0 1];
a=[i2(1) diff(i2)];
idx1=find(a==1);
idx2=find(a==-1);
if numel(idx2)<numel(idx1)
   idx2(end+1)=numel(a)+1;
end
out=arrayfun(@(x1,x2) i2(x1:x2),idx1,idx2-1,'un',0)

[the cyclist]

Azzi, sometimes I think you only answer questions if they require using arrayfun without uniform output! :-)

[Azzi Abdelmalek]

the cyclist, I did not understand what you mean?

[the cyclist]

I was just joking that because so many of your answers use arrayfun (and usually without uniform output), I wonder if you specifically look for questions that need that, and only answer those.

[Azzi Abdelmalek]

It's true, I 've used arrayfun several times, even when it's not the more efficient solution (because I'm not yet good with accumarray), for 'Uniforme output', it's dictated by each case,"I am not guilty!"

[Evan]

A good majority of my answers rely on arrayfun/cellfun as well (also regexp/regexprep). I think, for me, it's an unfortunate symptom of spending too much time playing Cody.

Answer 4

[Swapnali Gujar]

You can try below code. This code will give you output as a cell whose first 2 cells will have names as "cell_array1" and "cell_array2", since there are 2 times when 1s appear in your input array in continuation (i.e. first 4 times 1s and next 5 times 1s). Below each column name, you will find respective 1s of each scan.

clc
clear all;
arr = [26.81267  1;
       26.82500  1;
       26.83733  1;
       26.86200  1;
       37.41933  0;
       37.40700  0;
       37.39466  0;
       37.38233  0;
       27.08400  1;
       27.07167  1;
       27.05933  1;
       27.04700  1;
       27.02233  1;
       ]

size_arr = size(arr);
j=0;
scan = 0;
for i=1:length(arr)
    if((arr(i,2)) == 1.000)
       j=j+1;
       scan=j;
         if  (i<length(arr)) && (arr((i+1),2) == 1.000)
            j = j-1;
         end
         cell_arr{scan} = strcat('cell_array',num2str(scan)); %creates numbered cell arrays

      end 

end

%===== Now start storing the values into the cell arrays. 
index=1;
columns = length(cell_arr)
k=1;

     for i =1:length(arr)
         if(((arr(i,2)) == 1.000)) && (k<=columns)         
             cell_arr(index+1,k) = num2cell(arr(i,2));
             index = index+1;
         elseif (arr(i,2) == 0.000)&&((arr(i+1,2)) == 1.000)
              k = k+1;
              index=1;

         end
     end

%end of file

This will give you output as cell_arr =

    'cell_array1'    'cell_array2'
    [          1]    [          1]
    [          1]    [          1]
    [          1]    [          1]
    [          1]    [          1]
               []    [          1]

You may need further processing to access these columns separately as per your need.