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Peter Perkins

MathWorks

Last seen: 18 days ago |  Active since 2011

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Answered
Eventfilters with durations return wrong (amount of) rows?
Soc, I think you need test_table = timetable(milliseconds(1:5000).', linspace(0, 1, 5000).'); test_times = milliseconds([1101 ...

18 days ago | 1

| accepted

Answered
How do I reduce categorical array containing alternate spellings and formats?
Chris, something puzzles me. You say, "I have a categorical array of length ~ 10,000 and typical string length ~ 10 to 20. Acc...

25 days ago | 0

Answered
assign the fields of a structure correctly
Most of what's being shown in the responses is unnecessary. It's easier than that. No loops needed, not even ismember. 1) vertc...

1 month ago | 2

Answered
Error in Matlab Data Filtering from an Excel FiIe
This seems like a lot of unnecessary extra code. Let the table you read in do the work for you. %data = readtable('MLAT_Sat2.xl...

5 months ago | 0

Answered
Converting a cell array to can message timetable
I don't know much about the Vehicle Network Toolbox, but the following suggests that your code has two problems: ... >> ...

5 months ago | 0

Answered
Find max within due date and find max within due date by class section
This is much simpler than the accepted answers suggests. And you want to use categorical for categorical data, not text. %t = r...

5 months ago | 0

Answered
Unable to outerjoin two tables, Error message of 'Left and right key variables have incompatible types'
Jay, it's impossible to know what you are doing from what you've posted. outerjoin does work with ordinal key variables, so you ...

5 months ago | 0

Answered
Calculating with different date times
I would think you would want to compute performance at each speed measurement by interpolating heart rate, rather than computing...

5 months ago | 0

Answered
Reading Multiple Excel Files, Analyzing and Indexing
In a fairly recent (most recent?) version of MATLAB, you can do something like the following. First create some fake CSV files: ...

5 months ago | 0

Answered
Duration type doesn't preserve seconds accuracy
James, Stephen's response is what I would have said, but there are a lot of things in this post, and I thought I would add to St...

5 months ago | 0

Answered
How to output a for to a 10x27 table (for loop keeps overwriting the variable)
Marshall, the advice to try to vectorize is good advice, but if that's not possible, you might try something like at this: heig...

10 months ago | 0

| accepted

Answered
Customized datetime format within table
Vic, I think you want synchronize. tt1 = timetable([1;2;3;4;5],RowTimes=datetime(2023,1:5,1)) tt2 = timetable([6;7;8;9;10],Row...

10 months ago | 0

Answered
Line of Best Fit for a time series plot
There are a bunch of things you might mean by this, but here's one thing you might do. % set up random data Time = datetime(19...

11 months ago | 0

Answered
Direct calculations on tables - elementwise mean of n-tables
If I understand your situation correctly, data{1:end} is a "comma-separated list" of tables, and so mean(data{1:end}) in effect ...

11 months ago | 0

Answered
How can I compress a table
Here's another possibility, using rowfun, that returns a table containing tables, which maybe is easier to use than what you ask...

11 months ago | 1

Answered
Help with graphing table into line graph
This spreadsheet is kind of messed up, and I will let you figure out how best to read it in. Given that, it seems like stackedpl...

11 months ago | 0

Answered
How to finding GAPS in satellite access times.
There are ways to do this without loops, but the most straight-forward way (assuming the data are sorted by start time) is brute...

11 months ago | 0

Answered
Index and select rows from table
"I need to split the original data based on the categories of col5." You probably do not want/need to do that. Take a look at t...

11 months ago | 0

Answered
how can I get a list of the countries used by the mapping toolbox as a cell array?
Stephen seems to have answered your question, but also, you will find categorical useful for cleaning your data: countryList = ...

11 months ago | 0

Answered
I have a problem with my script. I would like to extract pH data from the coast of Cameroon or the Gulf of Guinea. Can I have some ideas on what is bugging my script and a cor
Using datenums is no longer recomended. t1=double(ncread([PathName,FileName],'TIME')); ... t(i)=datenum(1900,1,1,0,0,0...

11 months ago | 0

Answered
Change of frequency content after using the retime function
Julius, I'm definitely not any kind of signal processing expert, but I think what you want is resample, from the Signal Processi...

11 months ago | 0

Answered
Sampling and Filtering Table Data
Presumably you would have a timetable. If you have the Signal Processing Tbx, you should look at resample.

11 months ago | 0

Answered
How can I align deterministic signals?
Some of what SS shows might be easier with timetables: for i = 1:4 signal = load("ew_data"+i+".mat"); signal = signal.ans;...

11 months ago | 1

Answered
My exported EDF file is up to 100 times bigger than my imported EDF file
I don't know much about EDF, and there's no fil attached, but my guess is that the culprit is Voltage_V = vertcat(Data.EEG{:});...

11 months ago | 0

Answered
Plotting bar graph from website
Marcus, it looks to me like what you have is a year-by-month array. As others have said, those bars are mightily thin. Have you...

11 months ago | 0

Answered
Trouble with date conversion
Worth saying that if the file was a spreadsheet and contained things like 20230101 as numeric values, there's a conversion for t...

11 months ago | 1

Answered
How to get columns as 'struct' in timetable
Ludo, I'm not 100% sure I follow your question, but lemme take a shot. As Stephen shows, a variable in a table can be a struct ...

11 months ago | 1

Answered
How to get columns as 'struct' in timetable
For the record, you are correct that timetable is the recommended way to work with timestamped data, but there are no plans to a...

11 months ago | 1

Answered
Plotting double vs datetime (DD-MM-YY), only the year is used from the datetime
Paul, in addition to what Walter said, those mat files each contain a bunch of 23041xN variables. Likely you would benefit from ...

11 months ago | 0

| accepted

Answered
How to update leap seconds
James, there's no way for customers to update MATLAB with new leap seconds. The IERS data is built into a binary file. The last...

1 year ago | 0

| accepted

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