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Peter Perkins

MathWorks

Last seen: 1 day ago Active since 2011

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Answered
How to extract time series averaged over a region?
Keegan, there's a bunch of ways to do this, here's one that uses a timetable: >> lat = ncread("chl2020.nc","latitude"); >> lon...

2 days ago | 0

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Answered
How can I merge successive row values (sum of the values) of the column Y according to a condition in column X?
You want to do grouped sums, where the groups are defined by consecutive zeros in X. Once you have the groups defined as a new v...

2 days ago | 0

Answered
Stackedplot: Incorrect x-axis values & multi-variable usage
Jackson, you have a table, and while stackedplot knows to plot against time with a timetable, it can't know what to plot against...

2 months ago | 0

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Answered
How to do interpolation only if data interval is > than 3h?
StarStrider's suggestion of datetime and retime is the way to go. Also, like SS, I am mostly guessing at what you are asking for...

2 months ago | 0

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Answered
readtable decide which coloumns are read as string and which as number. xlsx file
Magnus, detectImportOptions and subsequent modifications on what it returns are what you are looking for. You can set any or all...

2 months ago | 0

Answered
How do I load only part of a table saved to a .mat file?
You might look into using datastores, which would, in effect, allow you to load pieces.

2 months ago | 0

Answered
Read variable in .mat workspace
Rachael, the times are not part of the data, they are "metadata". But as your screenshot shows, the row times of the Acceleratio...

2 months ago | 0

Answered
Table of tables. Subtables have variable height
Joanna, I suspect that you are 95% of the way there, but it's hard to tell. You say, "each column of subtables has the same widt...

2 months ago | 0

Answered
How to do a lookup for the best number that suits a condition between two arrays?
If you create gap as a row, and shim as a column, this is only a couple of lines. < will automatically expand the two vectors to...

2 months ago | 0

Answered
Why is my table displaying "1 x 1 table" instead of the actual values
It may be that your matrix1 is not a numeric matrix, but rather is itself a table. You have not provide enough information for a...

2 months ago | 0

Answered
How to tell two categorical arrays with different categories names are the same
You don't have categorical arrays, you have numeric arrays. If you had categorical arrays, you'd just look at their categories.

2 months ago | 0

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Answered
Separate multi-word comma separated cell into rows
[Edited to be even modern by using split, not strsplit, join, not strjoin, and double, not str2double.] Here's a more modern ve...

2 months ago | 1

Answered
Plot two x-axis in a graph with Time(calendar month/year) on axis and Hour on another x-axis
This made little sense to me until I realized that the times were elapsed times from the beginning of data collection i hours, a...

2 months ago | 0

Answered
How do you convert DateTime Strings into Date and Time values (seconds or month,day,time) Trying to plot wind speed by time
Cam, what problem are you having. Your screenshot suggests you have a vector of datetimes. Use that in plot, or whatever chartin...

2 months ago | 0

Answered
Subscripting into a table using one subscript (as in t(i)) is not supported. Specify a row subscript and a variable subscript, as in t(rows,vars). To select variables, use t(:
As the error message suggests, all you need is a colon as the second subscript. data = readtable('numfile.xlsx') ... dataTrai...

2 months ago | 0

Answered
Get and interpolate missed daily data
Tis is a one-liner with timetables and retime: >> tt = readtimetable("missed data.xlsx") Warning: Column headers from the file...

2 months ago | 0

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Answered
How to convert an excel file (.csv) to a .wav format/any other audio format file?
This should give a hint that xlsread is not the right way to go. In this case, you want to use readmatrix: a = readmatrix("w...

2 months ago | 0

Answered
Import values from excel to use it as content
You can index into a vector of your numic values with a categorical: >> opts = detectImportOptions("Book1.2.xlsx") >> opts.Var...

2 months ago | 0

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Answered
Inserting Date Time into code
You need to read 20141018_1.txt into a timetable so you have the timestamps for each for of rainfall data. Every other line in t...

2 months ago | 0

Answered
Combining many variables into one table
In recent MATLAB version, there's Simulink.Simulation.Dataset called extractTimetable. Not sure if that's what you have, but it ...

2 months ago | 0

Answered
Use loop to Summarize the Data using MATLAB
Not sure what you are trying to do. Maybe you are trying to get all the Energy data into one array? It's not clerar from your qu...

2 months ago | 0

Answered
Use timetable as x axis in heatmap
Amir, according to your screenshots, you do NOT have a timetable. You have a table containg one datetime variable, and a separat...

2 months ago | 0

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Answered
How do I combine rows of a 2D cell array with 1D cell arrays of varying lengths?
Mixed data are what tables (or timetables) are for: >> SID = ["sid001";"sid002";"sid003";"sid004";"sid005"]; >> Status = categ...

2 months ago | 0

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Answered
Compare columns of different tables and extract value
This sounds like you need a join. Also, probably a timetable: >> data = readtimetable('Thess_20062100.csv'); >> data.Daily_Tap...

2 months ago | 0

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Answered
Storing values in a matrix
This will be MUCH easier using a timetable. It's a one-liner: >> tt = timetable(rand(100,1),'RowTimes',datetime(2022,3,9,1:100,...

2 months ago | 1

Answered
How to place values in a matrix with values from another matrix?
This is a one-liner with join. You have time, so use a timetable: >> year = datetime([2018;2019;2020;2021;2022],1,1); x = [13;1...

2 months ago | 0

Answered
How to search a specific row and a column from a csv file that are associated with the date that was selected?
It's a LOT easier using a timetable: >> x = (1:20)'; >> y = rand(size(x)); >> date = datetime(2022,1,repelem(1:4,5)'); >> tt...

2 months ago | 1

Answered
Extracting information from multiple tables within a cell to plot
Here's a version that uses grouped rowfun and varfun to do the heavy lifting: load matlab.mat table_heightsPR = cellfun(@heigh...

2 months ago | 0

Answered
How to acess data if its in cell form?
This looks susp[iciously like another post: https://www.mathworks.com/matlabcentral/answers/1664149-i-have-a-list-of-data-and-i-...

2 months ago | 0

Answered
Create table from array in a loop
In addition to what Stephen has said, this code (which as Stephen points out was unncessary) V835 = rawTable((rawTable.x > 830)...

2 months ago | 0

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