Community Profile # Stephen23

Active since 2014

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extract number of columns in each row
Where C is your cell array: V = cellfun(@numel,C) V = cellfun('size',C,2)

11 hours ago | 1

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Function that outputs a varying number of variables depending on input --> N inputs = N output variables
"To my understanding I would be unable to use alternate methods given that the data I am loading are mutlidimensional arrays of ...

13 hours ago | 0

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To write a For loop in which a variable is updated with each run.
"I want to make this more efficient by using a for loop (if it can be done)." Of course it can be done, you just need to avoid ...

3 days ago | 0

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Using an array as an element in a function.
Use element-wise division ./ not matrix division / You will probably also need to use element-wise power .^, not matrix power ^...

3 days ago | 0

create cell array by extracting all the same row from multiple matrix
"Is this achievable through cellfun?" Yes: A = rand(105,3); B = rand(105,3); C = rand(105,3); D = cellfun(@vertcat,num2cell...

6 days ago | 0

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I want to enter a mathematical function as an argument to a function
The simple approach using a function handle: plot_compare(@sin , 5 ,20); plot_compare(@(t) 4*t+9 , 5 ,20); function plot_co...

7 days ago | 0

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How to create a table from strings and numerical data?
" I don't want to preallocate anything as the sizes are unknown. I wanna start with an empty table and then after first iteratio...

7 days ago | 0

Plot the last value from each cell from excel file
"Could you please provide me the best way to extract the last values in each cell and plot it?" Sure, I already did that sixtee...

7 days ago | 0

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Alternative to Eval for small number of variables
Approaches like EVAL and structure fields for this task are far too complex. You need to learn how to use arrays to write simpl...

8 days ago | 0

Convert input item into string
https://www.mathworks.com/help/matlab/ref/inputname.html

9 days ago | 1

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Extract value until regexp case match
Does the data you want to match always occur at the start of the string? A = "9/12/2022 7:38:51 PM 216 Indicator"; B = regexp(...

10 days ago | 1

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Sine Function I'm trying to Plot won't show up
"Not sure what I'm doing wrong here." You need to use element-wise division, not matrix division: phi = 0:0.1:6*pi; I2 = sin(...

11 days ago | 1

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replacing text in a string using indexing
For overlapping matches use STRREP. For non-overlapping matches use REGEXPREP: regexprep('qqqqqq','qqq','qwe') regexprep('qqq...

13 days ago | 0

How can I discretize data by their sign?
A = [-2,-1,5,-10,7,3,-9,-12,11]; B = sign(A); C = cumsum(logical([1,diff(B)]))

14 days ago | 0

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Skipping certain lines using fscanf
C = {}; [fid,msg] = fopen('polydata.txt','rt'); assert(fid>=3,'%s',msg) while ~feof(fid) C{end+1} = sscanf(fgetl(fid),'%...

14 days ago | 0

Creating Own Time Variable from Datetime Data
"I hope someone can help me convert my datetime time variable into working with a new time variable, thanks. " Your question do...

14 days ago | 0

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How inv() works ?
The INV documentation states "inv performs an LU decomposition of the input matrix (or an LDL decomposition if the input matrix ...

15 days ago | 1

Convert matrix into CSV, with each matrix element as a separate line including indices of matrix element
M = [0.5,0.1,0.6;0.9,0.8,0.3] N = M.'; S = size(N); [X,Y] = ndgrid(1:S(1),1:S(2)); writematrix([X(:),Y(:),N(:)],'test.txt') ...

16 days ago | 1

Why does the code have Check for incorrect argument data type or missing argument in call to function 'zero'?
Change the function from ZERO to ZEROS. ZEROS creates an array of the value 0: https://www.mathworks.com/help/matlab/ref/zeros....

18 days ago | 1

how filter "*.*" when using uigetfile function.
If there are no descriptors, the "All files" is automatically appened onto the end of the filter. The solution is to add descrip...

18 days ago | 0

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How to subtract ?
The simple MATLAB approach: S = load("allmat.mat"); M = S.allmat M(:,6) = M(1,6)-cumsum(M(:,5))

18 days ago | 0

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Creating a table by extracting rows from a table based off their values in relation to another table of a different size.
a = [11;33;55;77;99;23;45;67;89;87;65;43;10;1;3;5]; b = [22;44;66;88;12;34;56;78;98;76;54;32;21;2;4;6]; c = [2;2;2;2;4;4;4;4;6...

19 days ago | 0

I got wrong data when i use datetime convertfrom
S = load('time.mat'); D = S.time T = datetime(1800,1,1) + hours(D)

19 days ago | 0

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How to use the command window in order to make a script faster and interactive?
I had to write a script to carefully remove all of those numbers from the variable names and recreate the original MAT files acc...

19 days ago | 0

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Using diff(x) function to create a new table by subtracting values from the previous row
M = readmatrix('Data241.xlsx') [~,idr] = sort(isnan(M),1); [~,idc] = ndgrid(1:size(M,1),1:size(M,2)); A = -diff(M(sub2ind(siz...

19 days ago | 1

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Error in datetime array format for writing new matrix
Ah, fractional years. Here is one way to convert a fractional year (yes, even leap years) to datetime: format long G M = readm...

20 days ago | 0

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Matlab Vlookup/Indexing equivalent
DT = [datetime(2027,1,1,(0:4).',0,0);datetime(2028,1,1,0,0,0)] Y = year(DT); M = [2027,1.2,200,350;2028,3.7,200,350;2029,7.2,2...

20 days ago | 0

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How to interchange position of a matrix?
A = [3,1,2]; B = [2,3,1]; X = [2,1,3]; for k = 1:numel(X) X([A(k),B(k)]) = X([B(k),A(k)]); end X

20 days ago | 1

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