How idx runs and give its value ?

https://in.mathworks.com/matlabcentral/answers/64723-use-of-this-symbol

a=[34.8 31 29 26.7 39.5]; %dummy data

n=33;

[val,idx]=min(abs(a-n));

minVal=a(idx)

After running:

Now I am not clear when in answer idx=1

then how a(idx)=34.8 came

Even I am not clear about idx...why its values change everytime

Answer 1

[M]

abs(a-n) =

1.8000 2.0000 4.0000 6.3000 6.5000

then min(abs(a-n)) = 1.8, and the location of this minimum value (idx) appears at the first value of the vector.

Where is the problem ?