How to replace an integer in a vector with another vector?

How can you replace a single element in a vector with a vector? I tried using logical indexing but it says "In an assignment A(I) = B, the number of elements in B and I must be the same." Kindly help.Thanks in advance.

Answer 1

[Azzi Abdelmalek]

a=[1 2 3 4]
b=[10 20 30]
idx=find(a==2)
out=[a(1:idx-1) b a(idx+1:end)]

[Daniel Jonnakuti]

Thank you once again