# How to write xs[i]..xs[i+1] in Julia 1.5 , two dots

how to write in Julai 1.5

``````xs[i]..xs[i+1] in Julai 1.5

function make_intervals(N=10)
xs = linspace(0, 2, N+1)
return [xs[i]..xs[i+1] for i in 1:length(xs)-1]
end
``````

Paul

what does this suppose to do?

1 Like

Not sure but I guess that you are trying to construct an array of intervals, in this case you need `using IntervalArithmetic` and then inside the function use the constructor `interval(xs[i],xs[i+1])` or the macro `@interval(xs[i],xs[i+1])`

1 Like

Sorry for the format, used Julia on cell phone:

``````function make_intervals(a,b,N)
x = range(a,b,length=N+1)
return [[x[i], x[i+1]] for i in 1:N]
end
``````

Result:

``````julia> make_intervals(0,2,10)
10-element Array{Array{Float64,1},1}:
[0.0, 0.2]
[0.2, 0.4]
[0.4, 0.6]
[0.6, 0.8]
[0.8, 1.0]
[1.0, 1.2]
[1.2, 1.4]
[1.4, 1.6]
[1.6, 1.8]
[1.8, 2.0]
``````

PS: could you please spell Julia correctly, three times â€śJulaiâ€ť is a bit too much.

6 Likes

If you change `linspace(0, 2, N+1)` to `range(a, b, length=N+1)` as suggested by @rafael.guerra, the function works.

Note that you can also use the `mince` function:

``````make_interval(N=10) = mince(0 .. 2, N)

make_interval()
10-element Array{Interval{Float64},1}:
[0, 0.200001]
[0.2, 0.400001]
[0.4, 0.6]
[0.599999, 0.800001]
[0.8, 1]
[1, 1.2]
[1.19999, 1.4]
[1.39999, 1.60001]
[1.6, 1.80001]
[1.8, 2]
``````
1 Like

Sorry to take over your post but, what it is this â€¦ notation that you use ? My Julia says itâ€™s undefined.

1 Like

@HenriDeh, this thread concerns the package IntervalArithmetic.jl.