why is my plot blank?
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readtable ("LOGGER31.xlsx")
x = LOGGER31(:,"x_Datetime")
y = LOGGER31(:,"x_thermResistance")
plot (x,y)
2 commentaires
Stephen23
le 19 Fév 2023
Maybe your data consists only of NaNs, or perhaps you are plotting only one point (which by default has no marker... no idea whay that is the default). In any case, without your data we cannot do much more than guess.
Walter Roberson
le 19 Fév 2023
readtable() does not assign the results to a variable by default.
Réponses (2)
It looks like that the whole imported data is not taken for x and y to plot them. See - e.g.:
D = readtable('DATA_A.csv');
x = D.N;
y = D.V;
plot(x, y, 'k-')
grid on
xlabel('N')
ylabel('V')
Try something like this —
LOGGER31 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1300315/LOGGER31.xlsx', 'VariableNamingRule','preserve')
x = LOGGER31.('%Datetime');
x{1} = string(datetime(x(1,1),'Format','yyyy/MM/dd HH:mm:ss')); % First Element Has A Different Format
x = datetime(string(x), 'InputFormat',"yyyy/MM/dd HH:mm:ss", 'Format','yyyy/MM/dd HH:mm:ss'); % Convert All To 'datetime'
LOGGER31.('%Datetime') = x % 'LOGGER31' With Consistent '%Datetime'
VN = LOGGER31.Properties.VariableNames;
x = LOGGER31.('%Datetime');
y = LOGGER31.('%thermResistance');
figure
plot (x,y)
grid
xlabel(VN{3})
ylabel(VN{4})
The plot was blank because the ‘%Datetime’ values were not converting correctly. The first element converted correctly, however the others were all NaT (‘not a time’), equivalent to NaN for numeric values, since they did not have the same formats as the first element, even though they were valid values, as my code demonstrates.
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le 19 Fév 2023
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