How can I equate all values of one vector to another and get the value ? Please find the example below
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Rakesh Yadav Kodari
on 18 Feb 2019
Commented: Jos (10584)
on 18 Feb 2019
If I have
dataA = [1,2,3,4,5,6,7,8,9];
dataB = [0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1];
I need to equate for example: 1 = 0.1, 2=0.2, 3=0.3 so that if I ask value(7) it should display 0.7
Thank you in Advance.
3 Comments
Rik
on 18 Feb 2019
If your data is already paired, what exactly do you want to do? Mathematically it doesn't really make sense to equate them, as they are not equal. What do you want to use this for? Maybe then we can help you solve that problem instead.
Accepted Answer
Andrei Bobrov
on 18 Feb 2019
Edited: Andrei Bobrov
on 18 Feb 2019
dataA = [-496,-636,-52,175,-84,-248,-555,-423,34,-174]';
dataB = [-0.399609375000000,-0.512402343750000,-0.0418945312500000,...
0.140991210937500,-0.0676757812500000,-0.199804687500000,...
-0.447143554687500,-0.340795898437500,0.0273925781250000,-0.140185546875000]';
x = [-636,-84,34];
[lo,ii] = ismember(x,dataA);
out = dataB(ii(lo));
3 Comments
Stephen23
on 18 Feb 2019
Edited: Stephen23
on 18 Feb 2019
@madhan ravi: you are right, but only if all elements of x are members of dataA. Robust programming would not assume this, which is probably why Andrei Bobrov prefers ii(lo), thus allowing for non-member values without causing an error.
If a non-member value is unacceptable to the algorithm then it would still be better to use assert and write a specific error message, rather than just rely on the uninformative "Indices must be positive integers" that would occur otherwise.
More Answers (1)
Jos (10584)
on 18 Feb 2019
You can use logical indexing, a very powerful tool in Matlab
tf = dataB == 7
dataA(tf)
4 Comments
Stephen23
on 18 Feb 2019
Edited: Image Analyst
on 18 Feb 2019
@Jos: I guess that should be with double equals:
dataB(dataA == -496)
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