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# Peter Perkins

### MathWorks

Last seen: 5 days ago Active since 2011

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Extract SST data in a polygon from average monthly netcdf file

12 days ago | 0

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Model calibration for different dates
I would think that the best way to do this would be to put your data into a timetable, and use the rowfun function with the date...

12 days ago | 0

How to get a sum of coloumnn linked to datetime?
Create a timetable from your data, and use retime to aggregate it to monthly. It's one line of code.

3 months ago | 1

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How do I pull data between specific dates like Vlookup formula in Excel?
As Walter says, uses a timetable. >> tt = readtimetable("sampledata_uyyk.csv") [some warnings removed] >> tt = convertvars(tt...

3 months ago | 0

date and time string identification
"I have the following information obtained from a text-file date_hne: {'2014' '04' '01' '23' '46' '44.998300'}" I don't s...

3 months ago | 0

how to convert hours and minutes from decimals to datetime objects
Converting to string is totally unnecessary. Assuming the first variable in the table is already a datetime: >> t = datetime(20...

3 months ago | 1

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Effect of os clock change on timers
cr, this was a bug in earlier releases, and got fixed in R2021a.

3 months ago | 2

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Live Editor: Brace indexing changes Table to Struct
You can certainly post something like the table you have. In any case, if A is a table, then A.all is a variable in that table....

3 months ago | 0

How can I delete some specific rows from a matrix?
Surely you don't just have a list of dates. Presumably you have data at each date. Use a timetable to store all that. At that p...

3 months ago | 1

Select column in timetable based on value in table
Two steps: 1) Find the nearest sensor. This easy using interpolation: >> load("SL.mat") >> load("SensorLoc.mat") >> SensorLo...

3 months ago | 0

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Is it possible to use vertcat with dot notation?
Depending on what you are doing, you may find it convenient to turn that struct into a table (which wil automatically vertcat th...

3 months ago | 1

A very fast way to convert numbers into datetime ?
Syntactically, >> time = datetime("202210270954498", 'inputFormat','uuuuMMddHHmmssSSS', 'Format','yyyy-MM-dd HH:mm:ss.SSS') t...

3 months ago | 1

How to find specific elements in cell array not followed by another specific element?
If you have time and other data, think timetables (also Walter is right about categorical): action = categorical([1;3;2;4;1;3;2...

3 months ago | 1

Getting Data from Cell: Dynamic Structure needed?
Simon, what you should do depends very heavily on what you want to do with these data, i.e. what "take the value of the needed d...

3 months ago | 1

trying to find highest values in a time segment
It's not clear to me that Image Analyst's solution answers your question, mostly because your question is not very clear. If the...

3 months ago | 0

How to fix non-alignment issue when plotting multiple axes
Dinuka, if that's the plot you are looking for, I guess Voss' suggestion gets you there. But I might also add: y1=0.45 + .3*ran...

3 months ago | 1

Storing Variables in a loop to out put in a table
Make a timetable: i = (1:9)'; a = i-1; b = i.^2; c = i + rand(9,1); d = rand(length(i),1); e = rand(length(i),1); f = ran...

4 months ago | 0

Issue Plotting 2 different Values

4 months ago | 0

Coverting Timetable to Column Vector
Sam, it looks like you are ending up with a 7201x6 timetable whose variables are cell arrays, and each cell contains a 500x1 dou...

4 months ago | 1

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A very fast way to sort datetime (in "ascend" mode)?
It seems like the obvious response to Any way faster than this one ? [~, idx2] = sort(datenum(a), 1, 'ascend'); is to...

4 months ago | 1

Average of variables in timetable belonging to the same day over several years
Ziad, it seems that "dayofyear" is using "serial day number of year", and as you found, is lumping 29-Feb's with the non-leap 1-...

7 months ago | 0

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Compile data from excel sheets into a dataset with multiple tags
Charlie, I'm confused. I haven't followed all of what you code does, but it seems that you are lining up tables of different he...

7 months ago | 0

Only required the mean value out rather then every single value in a data
"7" sounds rather suspiciously like "weeks". If this were a timetable, it would be a one-liner with groupsummary. Moral: don't t...

8 months ago | 1

Using date and time in MATLAB
I'm having trouble following exactly what needs to be done, but I imagine you want to append variables to your LoadProfile&Tarif...

9 months ago | 1

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Help Merge two tables by the column variables
See join (or maybe innerjoin).

9 months ago | 1

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generate an independent seed with a fixed number
Ebru, you are doing parallel simulations and presumably want to combine the results under the assumption that those results are ...

9 months ago | 3

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Export rows as combined separate CSV files
There are a bunch of ways to do this. I thought I'd see how well rowfun works: > C = {rand(10,1) rand(10,1); rand(10,1) rand(10...

9 months ago | 0

Error: Row index exceeds table dimensions.
SOLARL.Date2 = datenum(SOLARL.Date); DON'T do that. Just use datetime. You can call unique, length, and == a on datetime vector...

9 months ago | 0