Stephen Cobeldick

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7,125 total contributions since 2014

Suspensa Vix Via Fit

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Answered
dynamically save a matrix to a structure
Do NOT use eval for trivial code like this. Your approach is slow, complex, inefficient, and not recommended. Rather than mess...

23 hours ago | 0

Answered
Conditionally select from array of struct by membership of a list in struct element
X(1).Members = [1,2]; X(1).Name = 'Group 1'; X(2).Members = [2,3]; X(2).Name = 'Group 2'; F = @(n)arrayfun(@(s)any(s.Members...

2 days ago | 0

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Answered
Can I somehow improve performance of str2double?
The fastest conversion uses low-level commands, e.g. sprintf and sscanf. Instead of this: C = {'1.2','3.4','5.6'}; V = str2dou...

3 days ago | 1

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Answered
How to sort one array based on the order of a second array?
As far as I can tell, the order of Q is irrelevant. A = ["1a","1b","1c","1d","1e","2a","2b","2c","2d","2e"]; % sorted B = ["A1...

3 days ago | 1

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Answered
Reshape array such that boundaries remain the same
x = [0, 1, 2, 1, 0]; y = [0, 0.5, 1, 1.5, 2, 1.5, 1, 0.5, 0]; xnew = interp1(x,linspace(1,numel(x),numel(y)))

3 days ago | 0

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Answered
Why am I getting "Array indices must be positive integers or logical values" error?
Consider this indexing: x1(i-j+1) What value does it have on the last iteration of the j loop? (hint: zero). i-j+1 % that ind...

3 days ago | 1

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Answered
Get unknown variable from mat-file
Given only one variable saved in the mat file: tmpC = struct2cell(load(filename)); myVar = tmpC{1}; Do not worry about the t...

3 days ago | 0

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Answered
Extracting the numbers from file names and listing them in a column
C = {'Rpma26siatBz 9.500000 Bx 0.000000mT WWait 2.000000Sec.Bzat9.5mT83.png',... 'Rpma26siatBz 9.500000 Bx 100.000000mT WW...

4 days ago | 0

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Answered
sum contents of array in groups of 10
Where V is your 1x3001 vector: M = sum(reshape(V(1:3000),10,[]),1)

4 days ago | 0

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How to append for each iteration not using cells?
Replace yield(p) = [yield(p); {helper(k)}]; with yield = [yield; helper(:)];

4 days ago | 0

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How to solve preallocating speed of a variable?
One simple solution is given here: https://www.mathworks.com/help/matlab/matlab_oop/creating-object-arrays.html "To preallocat...

4 days ago | 1

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Answered
Undefined function 'split' for input arguments of type 'char'
The function split was introduced in R2016b, so you will not be able to use it with R2013a. You can probably replace that line ...

4 days ago | 0

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Accessing data from a struct cell
Assuming that your structure is named S, you can loop over it like this: for k = 1:numel(S) plot(S(k).data) % default plot...

4 days ago | 0

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Convert cell array to vector
S = load('timestamps.mat'); T = vertcat(S.ans{:}) M = seconds(mean(diff(duration(T,'InputFormat','hh:mm:ss.SSS'))))

5 days ago | 0

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Answered
Create a Slanted Linspace Matrix
hankel(1:4,4:7)

5 days ago | 0

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Maximum number of repeated values over an array
a = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,9]; x = cumsum([true;diff(...

5 days ago | 1

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Answered
How to compare letters if they are same
Rather than building maps by hand, I would get Python to do the heavy lifting, e.g.: baz = @(v)char(v(1)); % only need the firs...

5 days ago | 0

Answered
How to convert time stamp 11:21:17.155 into seconds in MATLAB??
The most efficient solution: a = '11:21:17.155'; b = [60*60,60,1]*sscanf(a,'%f:')

6 days ago | 0

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Is it possible to make a loop where the the result is separate from the loop and have the result respectively with the input?
Use a cell array to store the data: p = 'Quantity of product you have bought today: '; n = str2double(input(p,'s')); c = cell...

6 days ago | 0

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Answered
"If function" can't distinguish i ~= 1.6.
"This weird thing only happens when i=1.6." Nothing weird happens: you generate binary floating point numbers using two differe...

7 days ago | 1

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replacing loop with cell of index values
s = 1:100; c{1} = 1; c{2} = 1:5; c{3} = 2:2:10; out = cellfun(@(x)s(x),c,'uni',0); out{:} A well-written (i.e. correctly p...

9 days ago | 1

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Answered
Colors in Matlab as a vriable
Perhaps something like this: M = [1,0,0;... red 1,1,0;... yellow 0,1,0]; % green X = strcmpi(Auto.Farbe,{'red','ye...

13 days ago | 0

Answered
Opening multiple .csv files using readtable
% opts is unchanged D = 'C:\Users\krist\OneDrive\Documents\MATLAB'; S = dir(fullfile(D,'*.csv')); for k = 1:numel(S) F =...

13 days ago | 1

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Answered
How to create matrix with other matrixes by joining them?
a = [1 2 3]; b = [4 5 6]; c = [7 8 9]; d = [10 11 12]; res = reshape([a;c;b;d],2,[])

14 days ago | 2

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Answered
saving the data in a variable
"...how to change the name of the file when matlab saves it" That is easy: https://www.mathworks.com/help/matlab/import_export...

14 days ago | 0

Answered
How to iterate over cell array, creating only unique combinations of cells
data = {1,2;3,4}; n = numel(data); m = nchoosek(1:n,2) % each row is one combination pair. out = data(m) % output [idr,idc] ...

14 days ago | 0

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Answered
how to arrange data into array
Without an intermediate sparse array: R = [1;2;3;4]; C = [10;11;13;15]; V = [1e-5;5e-5;10e-5;15e-5]; % S = max([R,C],[],1);...

14 days ago | 0

Answered
How to count the number of times that values changes?
A = [1;1;1;2;1;3;3;1;1] B = [NaN;cumsum(diff(A)~=0)]

15 days ago | 3

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Answered
Getting rid of loops
Logical indexing is much simpler than using loops: idx = A<1 & A>0; A(idx) = B(idx); A(A<C) = NaN; idy = B>100 | B<0; ...

15 days ago | 0

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Answered
How to conditionally merge rows in a table
lat = [45.67, 45.67, 56.89, 78.61]'; lon = [-66.45, -66.45, -65, -67]'; id = [202, 202, 201, 200]'; key = {'A', 'B', 'C', 'C'...

16 days ago | 0

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