# How do I add values to specific values/ specific place of an already existing array?

3 views (last 30 days)
Goncalo Costa on 13 Oct 2021
Edited: Chetan Bhavsar on 15 Oct 2021
I have an array of number, t , from which I have extracted some elements at even intervals (every 30 elements, one was extracted) into an array, A.
I now intend to select specific elements in A that meet a condition (if statement), and add x elements to it (x/2 to each side). These new elements to be added are the ones around those specific elements in t (x/2 in each side).
e.g. t = [1.5, 2.5 ,3.5, 4.5, 5.5 ,6.5, 7.5, 8.5, 9.5, 10.5] ;
A = [3.5, 5.5, 7.5],
and in this case I will choose x = 2 elements.
I want to add 2 elements from t to A and finish with A = [ 2.5 ,3.5, 4.5, 5.5 , 6.5, 7.5, 8.5 ]

Chetan Bhavsar on 13 Oct 2021
Edited: Chetan Bhavsar on 15 Oct 2021
@Goncalo Costa will this work for you?
t = [1.5, 2.5 ,3.5, 4.5, 5.5 ,6.5, 7.5, 8.5, 9.5, 10.5]
t = 1×10
1.5000 2.5000 3.5000 4.5000 5.5000 6.5000 7.5000 8.5000 9.5000 10.5000
A = [3.5, 5.5, 7.5]
A = 1×3
3.5000 5.5000 7.5000
x = 2
x = 2
reqx =x/2;
Index = arrayfun(@(x) findstr(x,t),A)
Index = 1×3
3 5 7
finalIndex =[];
for i=1:length(Index)
finalIndex = [finalIndex Index(i)-reqx:Index(i)+reqx]
end
finalIndex = 1×3
2 3 4
finalIndex = 1×6
2 3 4 4 5 6
finalIndex = 1×9
2 3 4 4 5 6 6 7 8
finalIndexUnique = unique(finalIndex)
finalIndexUnique = 1×7
2 3 4 5 6 7 8
2.5000 3.5000 4.5000 5.5000 6.5000 7.5000 8.5000
Chetan Bhavsar on 13 Oct 2021
@Walter Roberson Any better way i can handle below line as it changes size on every loop.
finalIndex = [finalIndex Index(i)-reqx:Index(i)+reqx]

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