How to index all but select indices?

Question

I have an array a=rand(100), I want to get every value except the values at the indices notidx=[2;50]. Is there a clean way to get a a

Answer 1

Update:

If you are using julia-v0.5+, you can also use the new generator expression, for example:

view(a, [i for i in indices(a)... if i ∉ notidx])

and

[a[i] for i in indices(a)... if i ∉ notidx]

Old post:

To get a copy, you can firstly make a copy of a, then manipulate it with deleteat! to delete those values at specific indices. After you've done this, it's convenient to get a view of a via indexin:

a = rand(100)         
# => 100-element Array{Float64,1}:
 0.62636  
 0.488919 
 0.499884 
 ....

b = copy(a)           
deleteat!(b, [2,50])  
# => 98-element Array{Float64,1}:
 0.62636  
 0.499884 
 ....

Answer 2

I don't have anything super clean, but you can do

a[setdiff(1:end, notidx)]

which is slightly cleaner than what you had, or

ind = trues(length(a))
ind[notidx] = false
a[ind]

which is pretty verbose but very clear.