# Dave B

### MathWorks

I am a software engineer at MathWorks. My work focuses on graphics and charting.

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**Content Feed**

How can I create an own callback function associated with several object? Like a 'refreshplot' callback function used in the 'PatientsDisplay.mlapp' app's example of Mathworks

In Code View, when you add the callback, just give them all the same name (see attatched gif)

environ 21 heures ago | 0

How to use the logspace function to create a vector of frequencies in Hz and not rad/s

To get logarithmically spaced values between 0.087 and 20: logspace(log10(.087), log10(20)) To be clear, logspace doesn't take...

1 jour ago | 0

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FFT plot in frequency domain, error help

What is size(Data) and size(fs)? Your function doesn't error for me when I give it a scalar fs and a vector signal: load hand...

1 jour ago | 0

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subplot command does not work

I think you wanted commas and not colons: subplot(2,1,1) plot(rand(1,10),'r') title('red') subplot(2,1,2) plot(rand(1,10)...

1 jour ago | 0

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I am Trying to Plot 3 plots onto the same graph

You can do this with hold on, just drop the calls to figure. figure(1); Vm=5.07; % Calculated on Paper Ttide = 1; % you d...

1 jour ago | 0

Parse error at u: usage might be invalid MATLAB syntax.

If you want to multiply you need a * y=-0.0811*u^3... Also consider if you want to raise a vector to the power of 3, you proba...

2 jours ago | 0

Undefined function 'trend' for input arguments of type 'double'

If you're trying to use a function you got from elsewhere (e.g. downloaded from file exchange) you likely need to add the direct...

5 jours ago | 0

How do I get my plots and "disp" script to show up after its respective code script has concluded?

What you describe that you want is the behavior I'd expect. I ran your code and got exactly this, but I made a few changes: I a...

5 jours ago | 0

How can I decrease the frame rate of a video?

Each iteration is going as fast as MATLAB can, you can slow it down with pause: videoReader = VideoReader('viplanedeparture.m...

5 jours ago | 0

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Turn off auto stretch for 3D plot in app designer

When you have an axes that you made in App Designer, gca won't return your axes. Can you try your set(ax,props,get(ax,props)) ap...

5 jours ago | 0

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How do I pull out from a table, the total mean of one item based on a particular condition (for several subjects), and then compute the difference in mean values?

You can do the first part with groupsummary Subject = [1 1 1 1 2 2 2 3 3 3 3]'; ItemA=[30 20 45 55 17 45 13 56 12 34 15]'; Co...

5 jours ago | 0

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display a shared legend for bar graph

There's an extraneous call to nexttile at the bottom, but after removing that I see what I'd call a shared legend....can you hel...

5 jours ago | 0

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Cumulative sum with condition

I think what you're looking for is groupsummary (or grouptransform): x=[rand(10,1) randi(3,10,1)]; % this is the sum for group...

5 jours ago | 1

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plotting a line of best fit using a for loop

you're plotting your x values against a scalar (Bfit(a)). I'm a little unclear about what you're tring to do here (your polyfit ...

5 jours ago | 0

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EEGLAB - Rename an event

In general, the excel-like find and replace can be done with strrep: bad = {'a' 'b"' 'c'} good = strrep(bad,'"','') But I'm...

5 jours ago | 1

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Subscripted assignment dimension mismatch error

When you write: U(1:ki,1:ki)=pi; You're trying to put a 150x1 into a 150x150...Maybe what you intended was: U(1:ki,1:ki)=repm...

5 jours ago | 0

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How can I create a plot with random directions?

It looks to me like left and backwards are kindof the same thing...how about adding x to differentiate them? foward = 1; left ...

5 jours ago | 0

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Error during Greyscale tiff image conversion to RGB tiff image

You have a small typo: tagstrut.PlanarConfiguration you missed a c, you wanted tagstruct.PlanarConfiguration

5 jours ago | 0

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Overlay barchart with subplots

Currently your code creates an axes, turns hold on, but then subplot creates a new axes that deletes 'ax' You can add a hold on...

5 jours ago | 0

Re-creating NeuroExplorer's perievent spectrogram with MATLAB

The function you're looking for here is spectrogram, but getting it to produce an something like NeuroExplorer will take some pa...

6 jours ago | 0

How to play a note

The Note you made is a logical: you're asking where abs(t) is less than or equal to (a bunch of stuff) If you want to play th...

6 jours ago | 0

How can I obtain a certain value from the function 'find' from a 3x2 cell?

I think you're asking how to search for the index of a row in a matrix based on multiple columns (although you have a cell array...

6 jours ago | 0

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prevent shaded areas from changing the colors of the bars.

First, you'll want the patch behind the bars, so call patch first. You can keep the transparency on the patch, but if you don't...

6 jours ago | 0

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Convert Cell Array into equation

I think you could use a combination of cellfun (to run on each cell) and eval (to evaluate the expression): a=readtable('matl...

6 jours ago | 1

Error: This statement is incomplete.

MATLAB won't distribute your j to all the locations in your print string, so you need a few more js. Have a look without the eva...

6 jours ago | 0

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programme matlab pour calculer et trace l'histogramme d'une image

im=imread('peppers.png'); % exemple d'image imshow(im) Si vous avez Image Processing Toolbox: figure imhist(im) Autrement...

6 jours ago | 0

A question about ismember function

Check out the documentation page here: https://www.mathworks.com/help/matlab/math/array-indexing.html (Indexing with Logical Val...

7 jours ago | 0

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My mesh grid is giving me a value not a matrix

The question is: how many points do you want in your grid? The : operator, by itself, takes increments of 1: 5:10 The min a...

7 jours ago | 0

Discrepancy between datenum and datetime?

This is one of the many reasons we have datetime, and why we recommend using datetime instead of datenum. If you can use datetim...

7 jours ago | 0

xlabel not working inside a function

You've named the function's parameters xlabel and ylabel. So within the function xlabel and ylabel are variables, not functions....

7 jours ago | 0

| accepted