How to find the index of the closest value to some number in 1D array ?
1 127 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
How to find the index in 1D array that has closest value to some number ?
val =-1.03
val1 = 1.04
x = -10:0.009:10
ind1 = find (A==val) % will work if the val is exact match
2 commentaires
Jose
le 15 Fév 2023
Modifié(e) : Jose
le 15 Fév 2023
Index=find(min(abs(Array-target))==abs(Array-target))
that should work even if the # of sig digits change in your array. It finds the location of value in the array, that when substracted from your target value has the smallest difference (i.e. closest match).
Din N
le 17 Mar 2023
This does give the closest value, but if you want the closest value to be smaller than your target value? For example if my target value is 7300, how can I specify here that I only want the index for the closest value that is smaller than 7300?
Réponse acceptée
per isakson
le 27 Mar 2015
Modifié(e) : per isakson
le 2 Avr 2019
Hint:
>> [ d, ix ] = min( abs( x-val ) );
>> x(ix-1:ix+1)
ans =
-1.0360 -1.0270 -1.0180
ix is the "index in 1D array that has closest value to" val
"if the val is exact match" that's tricky with floating point numbers
2 commentaires
Peter Kövesdi
le 2 Avr 2019
Take care: This routine fails with uint data types. Transform them to double first:
double(x);
or
double(val);
as needed.
Plus de réponses (3)
Peter Kövesdi
le 1 Avr 2019
ind = interp1(x,1:length(x),val,'nearest');
also does it.
But a short comparison shows disadvantages in timing:
f1=@()interp1(x,1:length(x),val,'nearest');
f2=@()min( abs( x-val ) );
timeit(f1)>timeit(f2)
1 commentaire
Andoni Medina Murua
le 18 Août 2022
Modifié(e) : Andoni Medina Murua
le 18 Août 2022
However
interp1(x,1:length(x),val,'nearest');
works in case val is an array, which doesn't happen with
min( abs( x-val ) );
Revant Adlakha
le 26 Fév 2021
You could also use something like this, where f(x) is the function and x is the value of interest.
ind = find(min(abs(f(x) - x)) == abs(f(x) - x));
1 commentaire
Voir également
Catégories
En savoir plus sur Matrix Indexing dans Help Center et File Exchange
Produits
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!