i want to get vectors of same length in my result.

Hello, need help in the following problem. BC is 1x99 and a(i), b(i) and c(i) are 1x30. and i want to plot BC vs a(i), but i am getting following error: In an assignment A(:) = B, the number of elements in A and B must be the same. any help much appreciated

data = load(FF);
mass = data(:,1); %extracting all rows of column 1
deq = data(:,16); %extracting all rows of column 16

BC = (15:10:995);

for i = 1:length(BC)-1;
    index = deq>=BC(i)-5 & deq<BC(i)+5;
    masstemp = mass(index);
    a(i) = min(masstemp);
    b(i) = median(masstemp);
    c(i) = max(masstemp);
end

[ANKUR KUMAR]

Could you please attach you mat file of variable FF.

[Jan]

Please post the complete error message, such that the readers do not have to guess, in which line the problem occurs.

Are you sure that the condition deq>=BC(i)-5 & deq<BC(i)+5 is fulfilled for all i? Maybe an index vector is empty.

[sud]

if true
  % code
endHELLO, I POST MY QUESTION AGAIN:
IdlCatalogue_Dir = 'C:\Users\yadav\Desktop\IDL_routine\OUTPUT_FILE\ROSETTE_S2_r5\'; 
File = 'ROSETTE_S2_r5_GeometricData.csv'; 
FF = fullfile(IdlCatalogue_Dir,File); 
Type = strrep(File, '_GeometricData_TOT.csv', '');
Type = strrep(Type,'_','\_');
rho = 0.917*(1e-4)^3; %converted to gm per cubic µm
data = load(FF);
mass = data(:,1); 
deq = data(:,16); 
BC = (15:10:995);
N = size(BC,99);
for i = 1:N-1;
  index = deq>=N(i)-5 & deq<N(i)+5;
  masstemp = mass(index);
  a(i,:) = min(masstemp,:);
  b(i,:) = median(masstemp,:);
  c(i,:) = max(masstemp,:);
end
figure()
scatter(N,a) 
hold on
scatter(N,b)
hol on
scatter(N,c);

i get the following error message: Error in bins_deq_mass (line 20) scatter(N,a) Error using scatter (line 62) X and Y must be vectors of the same length.

[sud]

i dont know why the format of my program changes when i write it here!!!!!

[Steven Lord]

Edit your message (click on the pencil icon between the flag and the trash can), select all your code, and press the "{} Code" button. That will format the code so it's easier to read.

[sud]

thanks a lot

[Stephen23]

"i dont know why the format of my program changes when i write it here!!!!!"

Because this website uses a very basic form of markup language to allow text to be formatted. You can learn more by reading the help at the top of this page, or with this tutorial:

https://www.mathworks.com/matlabcentral/answers/7885-tutorial-how-to-format-your-question

[sud]

thanks!

Answer 1

[Jan]

This line is a problem:

N = size(BC,99);

This replies the length of 99th dimension of the array BC. I'm sure, that you do not have a 99 dimensional array. But Matlab accepts this command, because there is the implicit assumption, that all trailing dimensions are be 1.

X = rand(2,3);
size(X, 3)
>> 1

In you code N becomes 1 and the loop:

for i = 1:N-1

is not entered at all, because it runs from 1 to 0. In consequence the variables a,b,c are not created. I guess, that the shown code is a script and that there are some values of former runs in the workspace.

1. Convert your code to a function to keep the workspace clean. Simply start the text with "function YourFcn".
2. Fix the size(BC, 99) command. I cannot imagine what is wanted here.
3. These commands look weird:

a(i,:) = min(masstemp,:);
b(i,:) = median(masstemp,:);
c(i,:) = max(masstemp,:)

This would be meaningful, if min is a matrix, then masstemp is an index and : means, that the complete rows are selected. The code in the original question looks better:

    a(i) = min(masstemp);
    b(i) = median(masstemp);
    c(i) = max(masstemp);

Here the minimum, median and maximum values of the vector masstemp are determined.

Finally, the error message is

 Error using scatter (line 62) X and Y must be vectors of the same length.

Your N is a scalar, and a,b,c have N-1 elements. This cannot work. What do you want to draw with these scatter commands?