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# Peter Perkins

### MathWorks

1,022 total contributions since 2011

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How to find the min, max and mean values of 34 timetables stored in a 1 x 34 cell and add them as extra columns to the respective timetables?
As others have said, it seems to make little sense to create new variables in each timetable, each of which are a column vector ...

24 days ago | 0

How to find streaks in a categorical vector?
diff is a numeric function. categorical is not numeric. Ordinal categoricals have a mathematical ordering, but they don't have a...

24 days ago | 0

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how to vector with the same length of matrix

24 days ago | 0

"do they have to be part of the table anyway?" polyfit doesn't accept tables, so yes and no. You will likely find the managemen...

24 days ago | 0

Time Series modeling/Predicting for GARCH
You were on the right track, it's just that you file contains two-digit year timestamps, and you need to specify that. Pragmatic...

24 days ago | 0

How can i select daily data with a 15 min partition?
These two things "only get the data for the day at 00:00. I want you to take all the data from those selected days" seem contr...

24 days ago | 1

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How to read from Excel columns into Signal analyzer app?
You must be leaving something out. If T.st is numeric, then T.st = seconds(T.st) creates a duration, and TT = table2timetable(T...

29 days ago | 0

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Separating timeseries into winter and summer months and removing night data
This is straight-forward using logical subscripting. No loops needed: >> t = datetime(2020,1,1) + hours(0:2:365*24)'; >> tt = ...

29 days ago | 0

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Calculate with same amount on every date and adjust when date changes (for-loop)
This is almost certainly simple to do with a timetable, no looping needed. Probably either retime or rowfun, plus cumsum. But ho...

29 days ago | 0

How can I convert datetime vector to datenum (class-double)
You almost certainly DO NOT want to convert datetimes to datenums. In recent versions of MATLAB, there are not many good reasons...

29 days ago | 0

Merge or join two data sets
You have an irregular intraday table (sentiments) and a daily timetable (returns). It sounds like you want to turn the sentiment...

1 month ago | 0

Import dates from csv files and plot them
Sarlota, I recommend that you use datetime, and not use datenum or datestr at all. Especially do not do this DateString = dates...

1 month ago | 0

How to check for gaps between datetimes in list of files in a folder?
Louise, if you really want one array that contains both time and text, timetable is the right thign to use (though I would argue...

1 month ago | 1

I have a timetable with 10 columns that are all binary and I want to add them together so I get a sum of those binary numbers for each row. Is there an easy way to do this?
There are several ways to do this, here's one particularly simple one. Assuming you are starting with something like this ... >...

1 month ago | 0

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Repeating a day of the year sequence from a specified date input
Right off the bat, 365 is a bug. I can't tell if you want to start at, say, 1-Oct-2020, and increment the day until you get to 3...

1 month ago | 1

Correlation Coefficient through time
"%(If you have any input in how to make these ^^^ calculations simpler I would also really appreciate any help)" Does this coun...

1 month ago | 0

How can I set time for x-axis plot in standard year, month,
I have no idea what that mat file is intended to contain. It's one double vector. In any case, don't use datetick. Just use dat...

1 month ago | 0

Calculate longterm daily average
grpstats is one good way to do this if you have Stats&MachineLearning. But you can do it with varfun or groupsummary as well, u...

1 month ago | 2

Retime puts all NaN
As Mohammad says, you must have times that are not exactly at the 5 minute marks. That's the danger of a short display format. ...

1 month ago | 1

Separate inhale and exhale duration
You don't need any loops. Your picture doesn't seem to match your description, but if each sret of four values corresponds to i...

1 month ago | 0

Removing a Date (Leap Year) from being Averaged
Not 100% sure what you are trying to end up with, but my guess is the average number of each type of complaint for each day of t...

1 month ago | 1

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Hi All,Remove empty [] entries row in Timetable, rmmissing is not removing rows which have empty entries, Please help, thank you very much
Amarkant, this ought to be a very simple operation, something involving rmmissing or maybe something like t = t(~ismissing(t.Va...

2 months ago | 0

Splitting groups into seperate tables
MLE, it's not clear what you have done, and what you want to do. splitapply on a table is for cases when you want to apply a fu...

7 months ago | 0

How to account for the day suffix when using datetime to recognise dates in matlab?
Pedro, you could put a literal th in the format, 'eeee dd ''th''MMMM yyyy hh:mm:ss a' and read most of them, and go back and ...

7 months ago | 1

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How to plot datetime in garfh?
Gili, you say datetime and table, so I'm going to assume you are using those datatypes. contour does not currently support datet...

7 months ago | 0

Datetime from csv: format change from 2017b to 2018 and higher
readtable now reads timestamps as datetimes by default. I think you have two options: 1) If you are already getting datetimes i...

7 months ago | 0

Reassign Categorical Variable Value
If you wanted to all the sundays into mondays, it would be easy: combinecats. But you want to turn them into either mondays or f...

7 months ago | 0

Convert empty table to zero
The answer might be >> t = table.empty(0,3) t = 0×3 empty table >> t{1,:} = 0 t = 1×3 table Var1 Var2 Var3 ...

7 months ago | 0

How to create a datetime vector from text input and sum only certain values?