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Campion Loong

MathWorks

Last seen: 4 jours il y a |  Actif depuis 2015

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Help extracting rows based on unique column 1 data
I would first put my data in a timetable. It is specifically built for time based data like yours. % Make some pretend data for...

plus d'un an il y a | 0

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convert excel time to time in a matlab
Simply use 'InputFormat' to parse the excel timestamp, and 'Format' to display it in your format of choice % Made up data - yo...

plus d'un an il y a | 0

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Extract data in a table following a a range of date (years)
I would use timetable for this kind of operations. It is specifically built for time based workflows. % Mock data for time betw...

plus d'un an il y a | 0

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Operator '-' is not supported for operands of type 'table'
If you are using table and addressing one variable at a time, dot subscripting (i.e. t.VarName(...) ) is often preferrable to br...

environ 2 ans il y a | 0

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how to concatenate two tables efficiently
"I am trying to read a huge amount of files, each file would have data stored in a atable in it" Have you tried using Datas...

environ 2 ans il y a | 0

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Extracting specific words from cells within a table column and moving them to new column
Good code indeed. This is almost the same code, but you could go deeper into string with missing handling in the Data Preprocess...

environ 2 ans il y a | 1

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Extract data from a table corresponding to specific time
Use timetable's logical or time-based subscripting to address your data with time expressively % Some clean up at import since ...

environ 2 ans il y a | 0

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Plotting high frequency EDF data from timetable
The stackedplot visualization for timetable is built for exactly this kind of use cases edfData = edfread('example.edf'); %...

environ 2 ans il y a | 1

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I have 2 columns in a matrix. 1st column has the dates. 2nd column has the values. How do I grab all values from 2nd column associated with its date from the 1st column??
This kind of tasks is what timetable is built for: % Using your small example tt = timetable(datetime(2018,4,[1;2;2;3;3;3]), [...

environ 2 ans il y a | 0

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How to add hours to the time data of one day
Alternatively, if you want to 'expand' every day into 24 hours as in your file, you could do this in two steps (starting with a ...

plus de 2 ans il y a | 1

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search content in table
If you are always using the values of d as a 'key' to look up other table variables, I would use straightly use d as the table's...

plus de 2 ans il y a | 0

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Is it possible to rename columns in a table?
Renaming table and timetable variables has become straightforward since R2020a: renamevars Rename variables in tabl...

presque 3 ans il y a | 2

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How to find the first date of each month in a datetime array?
Alternatively... % dateshift all dates to beginning of the month, and find the indices of the first unique entry [~,idx_first_...

presque 3 ans il y a | 0

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Access data from table and assign to variables
Picking up from @Ive J's example, but use 'Vehicle' as Row Labels to take advantage of native table indexing: t = table([50; ...

presque 3 ans il y a | 1

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How do I specify a variable from a table that uses words and not numerical values
I would use a categorical for trashTags. trash = readtable('Litterati_processed_data.csv'); trash.Tags = categorical(trash.Tag...

plus de 3 ans il y a | 0

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How to apply an 'AggregationFunction' with two variables in unstack ?
How about this? >> t_groupsum = groupsummary(t,'group','sum',{'var1','var2'}); >> t_groupsum.Properties.RowNames = t_groupsum....

plus de 3 ans il y a | 0

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How to Select Specific Time Intervals Over a series of time steps
I second Ameer's logical indexing approach. On the other hand, if this is representative of your data format, you may consider k...

plus de 3 ans il y a | 1

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speed up renamecats/categorical multiple columns
Hi Peng, It seems you have the Dictionary code book to boot, and you already know which sets of code go wtih which field/name i...

presque 4 ans il y a | 0

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Convert Table to double vector
Hi Ameer, If you have R2019a and newer, you can try using readmatrix to directly read the file as numeric: https://www.mathwor...

presque 4 ans il y a | 1

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Slow 2020a performance writing to a Table in a loop
Hi Charles, Thanks for bringing up this performance question. I assume from your code snippet the timing is done either in the ...

environ 4 ans il y a | 1

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Poor R2019b performance with tables
Hi all, Continuing our investment in performance, R2020a has been released with more indexing improvement in table, timetable, ...

plus de 4 ans il y a | 4

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Poor R2019b performance with tables
Thank you all for keeping track of table performance. First of all, we regret that the performance improvement in assigning i...

plus de 4 ans il y a | 2

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Match datetime within 3 seconds from two tables of different sizes
This is a good question! Basically, if I understand correctly, you want to extract rows from table_2 whose timestamp matches tha...

plus de 4 ans il y a | 3

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Use datatime data of one table to find (and write) the nearest datetime and corresponding value data in another table
Use timetable instead of table for timestamped data. You may use table2timetable to convert table to timetable; or use readtimet...

plus de 4 ans il y a | 2

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How to rearrange categoricals to a specified sequence
The categories of your categorical array is sorted in alphabetical order. % 'c' is your categorical array >> categories(c) an...

plus de 4 ans il y a | 0

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Find column with error and delete it
You can fine-tune how MATLAB imports your data using various Import Options (Create import options based on file content). First...

environ 5 ans il y a | 0

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sorting unique date by time.
As Steve suggested above, you should import the CSV into a timetable and unstack to get what you want. I'd also mention the dete...

environ 5 ans il y a | 0

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Reducing a cell array of tables to a single table
Hi Ingo, Glad you've found a solution. In case it maybe useful in your workflow, I'd like to mention the various Datastores a...

environ 5 ans il y a | 0

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How to interpret ButtonDownFcn event data for axis which limit is datetime?
As Walter suggested, pasting my <https://www.mathworks.com/matlabcentral/answers/357449-how-to-interpret-buttondownfcn-event-dat...

presque 7 ans il y a | 4

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Problem with 'keeplimits' for dates on figure x-axis
Hi Luc, I see that you are utilizing the |datetime| datatype <http://blogs.mathworks.com/loren/2015/02/12/introduction-to-the...

presque 9 ans il y a | 1

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