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Duncan Po

MathWorks

Last seen: 19 days ago Active since 2013

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Answered
Split arrays in table into separate rows
I think you can do what you want in several steps. % Convert your cell arrays in voxel_coord, R2s, and MT into arrays using cel...

1 month ago | 1

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Answered
Select a cell table
If you want the value in RESP0234_SOZ_TABLE{2,2}, use eval to evaluate that expression: for i=1:length(numbers); j=numbers...

1 month ago | 0

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Answered
Timetable_Averaging values from each month
Use groupsummary with 'monthofyear' binning T = timetable(datetime(2000,1:(12*21),1)', rand(12*21,1), 'VariableNames', {'USDM_i...

1 month ago | 0

Answered
Efficient way to standardize large amounts of text
You may be able to use patterns. For example, suppose the standard format is letters followed by underscore followed by numbers,...

1 month ago | 0

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Answered
How to solve the Operator '-' is not supported for operands of type 'table'?
z should be a matrix instead of a table. z is defined using parentheses indexing in your code: z = LSinclination(:,5); This re...

6 months ago | 0

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Answered
splitting column in table without creating new variables
Unstack may be the function you need to convert your table into a column for each trial, and then use braces indexing to convert...

6 months ago | 0

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Answered
Merge columns with different cell input
Can you convert your empty char '' into empty array []? Tables can be concatenated with empty array but not empty char: t = tab...

6 months ago | 0

Answered
plot specific time points of everyday in an automated data
See this example of checking the hour component of a datetime, and then using logical indexing to extract a time range: dt = da...

6 months ago | 0

Answered
Plotting acceleration vs time on Matlab from accelerometer data that doesn't have a time column
You can create a timetable, and just supply the start time and frequency. Timetable will compute the timestamps for your data. F...

6 months ago | 0

Answered
Accessing data in matrix entries of tables
You can use multiple sets of curly braces {} to index into cells, and then use parentheses to index into the resulting arrays, l...

6 months ago | 1

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Answered
Categorize data in if else statement
You can discretize the BMI values into categories and then count them, like this: >> c = discretize(BMI, [0 18.5 24.9 29.9 34.9...

6 months ago | 1

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Answered
Find maximum for each Image in table
You can use groupsummary to find the maximum value of each group: T1 = groupsummary(T, 'MaxPosition', 'max', 'Intensity');

6 months ago | 2

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Answered
creating table of finely spaced xy points that represent a box corner
meshgrid may be the function you are looking for. For example, >> [x,y] = meshgrid(1:5,1:5) x = 1 2 3 4 ...

6 months ago | 0

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Answered
Rapid access and data manage of a table with cell array in the columns
You can use cellfun. For example, to compute the maximum of each column of the H3raw cell column for each row, do this: cellfun...

9 months ago | 0

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Answered
Plotting Timetable in Matlab
The line: Time=TR({'05-05-2020','05-06-2020 00:00:00'},:); only extracts two rows from TR. So Time only has two rows. Then w...

9 months ago | 0

Answered
Grouping based upon differences in time, with some small scatter
One way to do this is to use isbetween in a for loop, and then unique(, 'rows') to find the groups: t = datetime({'27-Aug-2020 ...

9 months ago | 0

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Answered
How can I track time periods under certain criteria?
You can put your data in a timetable and then use movsum like this: tt = readtimetable('Daily_Data_Thessaloniki.xlsx'); tt.thr...

9 months ago | 0

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Answered
PLOT ACTION IN TIME LAPS
Your data is best represented as a timetable in MATLAB. You can then use stackedplot to generate the visualization. haa = readt...

9 months ago | 1

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Answered
Spatial correlations with a timeseries
corr works on columns in 2D matrices. Your local temperature is a row, so you need to tranpose it: local_temp = local_temp...

9 months ago | 0

Answered
Combine timetables vertically different variables
You can use outerjoin with MergeKeys option set to true. You need to specify your common variable names (in addition to 'Time') ...

2 years ago | 1

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Answered
How to stackedplot with text data
What do you expect to see with your text data in the plot? stackedplot ignores text data, but plots categorical data. If your ...

2 years ago | 0

Answered
What unit does the frequency have (MATLAB Color Histogram)?
The Y axis is number of pixels. The image in the example is 384x512, so it has 196608 pixels.

2 years ago | 0

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Answered
Help with creating histogram
If you convert to categorical, you can sort the counts by descending order: a = randi(10,10,10); histogram(categorical(a), 'Di...

2 years ago | 0

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Answered
Is there a way to plot multiple graphs in one "subplot" of a stackedplot figure?
stackedplot can plot multiple lines in the same axes. One way is to have a non-column matrix as one of your table variables: x ...

2 years ago | 3

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Answered
I can't plot two lists as histograms as different colors on the same plot. Hist wants 'Numeric Input'
What does class(list1) return? If it returns anything other than a builtin numeric class, that would be the reason for your erro...

4 years ago | 0

Answered
arrange multiple 2D histograms in 3D
You can use the hist function to plot one histogram, then grab its vertices from the resulting patch object. Pass these vertices...

5 years ago | 1

Answered
how to extract subbands from pyramidal directional filter bank/contourlet decomposition of an image?
You need the contourlet toolbox: <http://www.mathworks.com/matlabcentral/fileexchange/8837-contourlet-toolbox>

5 years ago | 0

Answered
Two bar graphs - two data sets - different bin width
histogram/histcounts have builtin support for Freedman-Diaconis rule: histogram(x, 'BinMethod', 'fd') or [n, binedges] ...

5 years ago | 0

Answered
When brushing 3-d scatter, why does the marker not change?
Are you using R2014b? There is a bug in that version. Good news is it is fixed in 15a, so if you update, brushing on scatter3 wi...

5 years ago | 1

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Answered
How to do sliding window operation in Matlab?
R2016a has a new function movsum: >> x=[4,1,1,1,2,2,3,5,9,7,7,7,6,6,1,1,2,3,4,4] >> movsum(x,10,'EndPoints','discard') ...

5 years ago | 2

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