How to combine 4 columns of a table into one new variable and plot it with respect to time?

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Mark Lupas 2020-4-13

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https://ww2.mathworks.cn/matlabcentral/answers/517587-how-to-combine-4-columns-of-a-table-into-one-new-variable-and-plot-it-with-respect-to-time

编辑： Mark Lupas 2020-4-13

I am reading from a file that has 7 columns. I imported it into a table, and I converted T.Var1 into UTC hh:mm:ss:FFF time. T.Var2, T.Var3, T.Var4 and T.Var5 all need to be combined into the variable "source" so I can plot it against timeUTC. Then I would like to have the user change the range of source that is being plotted, where they would be able to chose the range of T.Var2 to be from x to y for example.

clear
clc
close all
[FileName,PathName]=uigetfile(':','Select the LYLOUT file');
T=readtable(fullfile(PathName,FileName));
timeUTC = (datestr(seconds(T.Var1),'HH:mm:ss:FFF'));
sizeTimeUTC = size(timeUTC);
figure('units','normalized','outerposition',[0 0 1 1]); 
plot(size,'b')
NumTick = 10;
set(gca,'XTickLabelRotation',45);
xticks=linspace(1,sizeTimeUTC(1),NumTick);
set(gca,'XTick',xticks);
set(gca,'XTickLabel',timeUTC);

How would I go about doing this?

EDIT: Here are the first few rows of the table as requested.

9601.762212787 33.70270888 -85.26950474 311276.18 0.04 24.4 0xa51
9601.833916448 33.57688907 -82.95670785 183351.65 2.57 23.5 0x358
9604.167990668 33.69930560 -83.95209122 38865.36 0.69 9.5 0xb18
9604.906035077 34.16707482 -85.25531467 12077.34 1.93 13.3 0x358
9605.012282662 34.20090438 -85.37965820 7081.78 3.71 18.4 0x368

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Adam Danz 2020-4-13

编辑：Adam Danz 2020-4-13

Why do you need to extract columns from the table? You can plot them and specify the range (ie, rows) directly from the plotting function.

If you need help thinking that through, share the first few rows of your table so we can see what you're working with. See head().

Mark Lupas 2020-4-13

编辑：Mark Lupas 2020-4-13

So I just plot the whole table and specify the range in the plot function?

EDIT: The data variables for an individual source is Var2, Var3, Var4 and Var5. I wish to plot an array of Source against timeUTC, where the user can specifiy the ranges of each data variable in source.

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Answer 1

Adam Danz 2020-4-13

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/517587-how-to-combine-4-columns-of-a-table-into-one-new-variable-and-plot-it-with-respect-to-time#answer_425799

在 MATLAB Online 中打开

Example:

plot(T.Var1, [T.Var2, T.Var3, T.Var4, T.Var5])

If you need to select certain rows,

idx = T.Var1 > x1 & T.Var1 < x2; 
plot(T.Var1(idx), [T.Var2(idx), T.Var3(idx), T.Var4(idx), T.Var5(idx)])

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Adam Danz 2020-4-13

在 MATLAB Online 中打开

There are lots of ways to ask users for input.

https://www.mathworks.com/help/matlab/ref/inputdlg.html

https://www.mathworks.com/help/matlab/ref/input.html

etc...

To convert string to datetimes (which are much more useful),

datetime(T.Var1,'InputFormat','hh:mm:ss:SSS')

For other format options: https://www.mathworks.com/help/matlab/ref/datetime.html#d120e246650

Mark Lupas 2020-4-13

编辑：Mark Lupas 2020-4-13

在 MATLAB Online 中打开

Thank you!

Sorry, one last thing. When I try

datetime(T.Var1,'InputFormat','hh:mm:ss:SSS')

it comes up with this error

Numeric input data must be a matrix with three or six columns, or

else three, six, or seven separate numeric arrays. You can also

create datetimes from a single numeric array using the 'ConvertFrom'

parameter.

But when using 'ConvertFrom' there isn't an 'hh:mm:ss:SSSS' option of any kind.

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