Stephen Cobeldick

6,086 total contributions since 2014

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Answered
a easier way to do vector
"Is there any easier or more efficient way to calculate SF when there is different k?" Do NOT use numbered variables, they are ...

2 hours ago | 0

Answered
Starting from the year 1697, store all leap years until 2017 in a vector. A leap year is a year which is divisible by 4 but NOT 100 but if the year is divisible by 100 then it must also be divisible by 400 to be considered a leap year.
You made a good start, all you need is to use indexing or concatenation to store the values that you want to keep, e.g.: lpy = ...

2 hours ago | 0

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How do I get two values of a function when using a loop?
You are only calling the function with one output argument. If the function returns two output arguments and you want both of th...

2 hours ago | 0

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vectorisation a for loop
Real vectorized code (no loop or arrayfun): eta = exp(-c*abs(bsxfun(@minus,dist,dist(:)))); discrim = 1./sum(eta,1) Or for MA...

2 hours ago | 0

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How to access object loaded into a struct when object variable name (as saved) is unknown
"I have tried every variation of indexing I can think of..." Indexing is entirely independent from fieldnames, so indexing like...

16 hours ago | 0

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How can i append cell arrays
C{2}{3} = 45

22 hours ago | 0

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Collapsing nested cell array values into simple numerical array
"I have used regexp to find some numbers in each element of a cell array." If the regular expression only needs to match once, ...

4 days ago | 0

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Answered
I really need help with fprintf'ing a string, having it alternate with commas and parentheses.
[~,idx] = ismember(coords,xy.','rows'); % Better: obtain these indices from your function! mat = [idx,coords].'; % should have ...

4 days ago | 0

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How to display the celcius sumbol (°C) using fprint??
Here are four methods: fid = fopen('temp.txt','wt'); fprintf(fid,'symbol one: °C\n'); fprintf(fid,'symbol two: %cC\n',176...

4 days ago | 2

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Answered
Values in cell array keep getting overwritten
Much simpler and much more robust: D = 'path to the main directory'; S = dir(fullfile(D,'img*')); for k = 1:numel(S) F =...

5 days ago | 1

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Answered
2D Convex Hull: I can't think of a 'criteria' to filter out the 'wrong' points, please help!
"I can't think of a 'criteria' to filter out the 'wrong' points." The obvious criteria to pick is in the name convex hull: why ...

5 days ago | 0

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Concatenate I x J*2 x K matrix in I*J x 2 x K matrix
Use reshape and permute, e.g. for two columns: >> A = randi(9,8,4,6); % fake data >> A(:,:,1) ans = 9 1 4 6 7 ...

5 days ago | 0

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Answered
How to use spacing around operator?
This is explained in the MATLAB documentation: https://www.mathworks.com/help/matlab/matlab_prog/case-and-space-sensitivity.htm...

5 days ago | 0

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Finding maximum number location in a matrix
"Is there a reason why this line is wrong?" Yes, because you nested max inside find. Take a look at the output of max: what is ...

5 days ago | 0

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Answered
Vectorized implementation for using a vector as an index for matrices
Use sub2ind like this: >> m = 7; >> V = randi([1,10],1,m) V = 9 10 2 10 7 1 3 >> A = zeros(m,10)...

5 days ago | 0

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Answered
saving multiple .mat files with the same name from a script
"Is there any way it could be save as data1.mat, data2.mat ......data20.mat (if i run the script 20 times)..." You could downlo...

5 days ago | 0

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If I have a logical vector created by ISDIR attribute of DIR, how to have its order by the date of the last modification of folders???
Simpler and much more robust: S = dir('D:\= BIO-PD ='); S = S([S.isdir] & ~ismember({S.name},{'.','..'})); % folders only, exc...

7 days ago | 0

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Answered
How to find all letters before a character in a char variable
>> secretMes = [';,.T234h467e#i`12n390@%f&^%o1@45r1%^m]\a131@t2i*/-o+/1n#i*895n#t$5&&h1/!i@$$s#f18945@i2/le#i98s#c`$%o%^n77*f(=i...

7 days ago | 1

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Data Sorting (looking for a range that do not exist in a list of numbers)
>> V = [1,2,3,6,7,8,23,24,25,76,77]; >> X = diff(V)~=1; >> B = V([X,false])+1 % missing range begin values B = 4 9 ...

8 days ago | 0

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Random shuffle vector such that all elements fall in new index positions
What you describe is called a derangement. You can download FEX submissions that perform derangements, e.g.: https://www.mathw...

9 days ago | 0

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Need to sort the number in the increasing order using MATLAB script, shown as a sample text file.
You could download my FEX submission natsort: https://www.mathworks.com/matlabcentral/fileexchange/34464-customizable-natural-o...

9 days ago | 0

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loop over subfolders and saving cat parameters
If you only need to loop over subfolders then why are you using three loops? One loop for the subfolders, one loop for the files...

10 days ago | 0

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Why [] appears after a function?
According to the function documentation, those square brackets contain any output arguments. Because the square brackets you sho...

10 days ago | 1

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Generate an array with random numbers from M to N using the command randi
>> R = [2,5]; >> rng('default'); >> A = randi(R,3,8) A = 5 5 3 5 5 2 5 2 5 4 ...

10 days ago | 0

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Help I keep getting error: [Error using griddedInterpolant The grid vectors must contain unique points]
Your grid data points are not unique (which they must be to perform interpolation): >> U = unique(X(:)); >> C = hist(X(:),U); ...

10 days ago | 0

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Answered
Extract partial data from vectors in structure
>> S.A = 0:3; >> S.B = 4:9 S = scalar structure containing the fields: A = 0 1 2 3 B = 4 ...

10 days ago | 0

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Answered
How to loop through the same operation on multiple variables
"Is there a way to shorten this into a loop?" By far the simplest and most efficient solution is to use a cell array and indexi...

10 days ago | 0

Answered
Loading part of a structure in a .mat file
The matfile documentation states "The MAT-file object does not support indexing into... Cells of cell arrays..." This means you...

10 days ago | 0

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Answered
Creating averages for parts of an array in a for loop
Your definitions of the boundary cases make this a bit tricky, but here is one solution: >> A = randi(9,1,10) A = 3.00 2...

12 days ago | 0

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swapping rows in a matrix
>> X = [1,3]; % rows to swap >> M = randi(9,4,5) M = 6 7 6 2 9 2 3 2 1 1 1 6 9 7 9 4 ...

12 days ago | 1

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