Rounding set of number to closest number in array

This is the data I need to round up to. Basically, each number from x_n I need them to get rounded up to closest number in yaxis array.

Y = round(x_n, yaxis) I have tried using this command but it says "The second input must be a real integer scalar." Then I have tried making a for loop putting each data separately, but I am struggling on what command to use to round it up to closest number from an array.

yaxis = [-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.60 0.8 1]

x_n = 0 0.5878 0.9511 0.9511 0.5878 0.0000 -0.5878 -0.9511 -0.9511 -0.5878 -0.0000

0.5878 0.9511 0.9511 0.5878 0.0000 -0.5878 -0.9511 -0.9511 -0.5878

Thank you for the help.

Answer 1

[Ameer Hamza]

Following shows a general approach

yaxis = [-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.60 0.8 1];
x = [0    0.5878    0.9511    0.9511    0.5878    0.0000   -0.5878   -0.9511   -0.9511   -0.5878   -0.0000 0.5878    0.9511    0.9511    0.5878    0.0000   -0.5878   -0.9511   -0.9511   -0.5878];

[~, idx] = min(abs(x-yaxis.'));
x_rounded = yaxis(idx)

Since yaxis vector is regular, there might be a more efficient approach.

[Damir Kadyrzhan]

Thank you! It worked. Can I also ask, what 'idx' mean in this code, because I can't really understand it.

[Image Analyst]

Yes, very understandable. My number one advice to programmers is to use understandable and descriptive variable names, even if they're longer, because the code will be more readable. My number two advice is put in way more comments than you think you need. His idx is the index at which the difference between x and yaxis is minimum. So x is closest to y at that index (array element). So I would have written the code like:

[minDifference, indexAtMinDiff] = min(abs(x - yaxis.'));
x_rounded = yaxis(indexAtMinDiff);

Hopefully that's self explanatory now.

[Ameer Hamza]

idx is the index number. It tells which element number in 'yaxis' is closest to the corresponding element in 'x'. You can run both lines one by one and see the output. It will help in understanding the code.

[Ameer Hamza]

@Image Analyst, thanks for your suggestions.

Answer 2

[Fangjun Jiang]

interp1(yaxis,yaxis,x_n,'nearest')

Answer 3

[Mathieu NOE]

hello

I think this function should do the job

all the best