Insert NaNs (or any value) in several position of a vector

Question

Luca Amerio 2015-9-11

1
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/242418-insert-nans-or-any-value-in-several-position-of-a-vector

回答： Juliana Damaceno 2019-1-23

采纳的回答： the cyclist

在 MATLAB Online 中打开

Hi i have a vector like this

a=[1 2 3 5 6 7 9 10 13 14];

I would like to find where the diff is bigger than a value (let's say one) and insert a NaN between the two positions. I need this to plot a discontinuous line that is interrupted if the X value grows too much.

I tried something like

ind=diff(a)>1
for i=1:length(a)
   if ind(i)
      a=[a(1:i),NaN,a(i+1:end)]
   end
 end

the problem is that whenever I add a NaN the followig value of a get shifted by one positiona and the positions in ind are no longer valid. I could shift ind too or I could copy each value of a into b adding NaN etc etc...

But they all seems over complicated method. Anyone got a good idea on how to do it?

thanks

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Answer 1

the cyclist 2015-9-11

4
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/242418-insert-nans-or-any-value-in-several-position-of-a-vector#answer_192012

在 MATLAB Online 中打开

Here is one way:

a=[1 2 3 5 6 7 9 10 13 14];
insertNanIndex = [0 diff(a)>1];
insertValue = (1-insertNanIndex)./0;
b_tmp = [a; insertValue];
b = b_tmp(:)';
b(isinf(b)) = [];

Notice that I temporarily fill in "Inf", and then extract it. So, if your original dataset has "Inf" in it, you will need to do a different dummy var.