Plotting non zero elements of an array

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Malte Römer-Stumm
Malte Römer-Stumm 2022-4-11
评论： Malte Römer-Stumm 2022-4-12
I have one array with x-values (X) and y-values (Y) and I want to plot selected lines of those within a loop.
The arrays X and Y have a shape like this:
482.8410 485.8150 487.6960 487.4730 489.4050 491.1900 491.3960 491.8090 0 0
611.4260 612.8240 617.4750 621.8790 622.2030 623.4460 623.0670 622.8820 0 0
355.5830 355.9290 356.7860 0 0 0 0 0 0 0
0 383.2500 385.3630 387.5590 389.0450 394.2830 396.2180 397.0960 395.4490 395.4630
X and Y have zeros in the same spots, only the non zero values differ. X and Y have a third dim, but for this context only layer 1 is relevant. I want to plot chosen lines individually and only the non zero elements from that line. I use the following plot command:
plot(X(temp,find(X(temp,:,1)>0==1),1),Y(temp,find(Y(temp,:,1)>0==1),1), 'r+', 'MarkerSize', 5, 'LineWidth', 2);
The variable temp is a line vector (i.e. 2 3 4) containing the lines, which are supposed to be plotted. I get the error:
Index in position 2 exceeds array bounds (must not exceed 10).
Error in Bubble_movement_analyser (line 424)
plot(X(temp,find(X(temp,:,1)>0==1),1),Y(temp,find(Y(temp,:,1)>0==1),1), 'r+', 'MarkerSize', 5, 'LineWidth', 2);
Additionally I get the comment, that using logical indexing would improve code perfomance, but I couldn't figure out, how to write that.
Does somebody knows why the Index in position 2 exceeds 10 or how to express this with logical indexing?

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回答（1 个）

DGM
DGM 2022-4-11
Try this instead.
plot(nonzeros(X(temp,:,1)),nonzeros(Y(temp,:,1)), 'r+', 'MarkerSize', 5, 'LineWidth', 2);

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