how to not plot NaN but still have same array length
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I have y = array of 10000 data. A lot of them are NaN. I dont want to plot NaN but if I use plot(y(~isnan(y)),'o'); my plot only goes up to ~1000. It should still go up to 10000 but not plot those with NaN. How can i do this ?
1 个评论
Mario
2026-6-27，12:46
just add xlim([0 10000]) after the plot expression without ~isnan
采纳的回答
Star Strider
2016-11-25
The NaN values themselves will not plot. This may produce breaks in the plotted line, so if you don’t want the breaks, your only option is to interpolate.
The easiest way to interpolate is to keep your original independent variable to be your interpolating variable, the eliminate all the NaN values from your dependent variable and the corresponding values of you independent variable, then use interp1.
Example:
x = 1:10;
y = [2 4 2 9 NaN 3 1 NaN 6 10];
xs = x(~isnan(y));
ys = y(~isnan(y));
yi = interp1(xs, ys, x, 'Linear');
figure(1)
subplot(2,1,1)
plot(x, y)
grid
subplot(2,1,2)
plot(x, yi)
grid
2 个评论
RuiQi
2016-11-25
Star Strider
2016-11-25
The data that are NaN will be invisible on the plot.
MATLAB does not plot NaN values, so you can just use your original data in your scatter plot without any modification.
If you also want to eliminate them from your data, use code similar to what I used to create ‘xs’ and ‘ys’, then plot those.
更多回答（1 个）
Image Analyst
2016-11-25
Your code basically extracts the non-nan elements and plots only those so it won't go all the way up to 1000. You need to plot x also to have it still go up to 1000. See this little demo:
numPoints = 200; % Make 1000 if you want. I used 200 to make it easier to see what's going on.
% Make sine wave sample data.
x = 1 : numPoints;
period = 200;
y = sin(2 * pi * x / period);
% Introduce 80 nans
nanLocations = randi(length(x), 1, 80);
y(nanLocations) = nan;
% Plot entire array, even the nans, which won't appear.
plot(x, y, 'bo-', 'LineWidth', 2);
grid on;
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')
2 个评论
atek
2018-2-9
what if y(1:100) = NaN? Matlab begins plotting at first real value, and I want it to plot NaN's as blank spaces
Walter Roberson
2018-2-9
Use xlim() to force the left boundary to start at 0
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