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
le 18 Fév 2019
Commenté : Jos (10584)
le 18 Fév 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 commentaires
Rik
le 18 Fév 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.
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Andrei Bobrov
le 18 Fév 2019
Modifié(e) : Andrei Bobrov
le 18 Fév 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 commentaires
Stephen23
le 18 Fév 2019
Modifié(e) : Stephen23
le 18 Fév 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.
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Jos (10584)
le 18 Fév 2019
You can use logical indexing, a very powerful tool in Matlab
tf = dataB == 7
dataA(tf)
4 commentaires
Stephen23
le 18 Fév 2019
Modifié(e) : Image Analyst
le 18 Fév 2019
@Jos: I guess that should be with double equals:
dataB(dataA == -496)
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