# Why size(vector, 2) return 1?

**URL:** <https://discourse.julialang.org/t/why-size-vector-2-return-1/89166>\
**Category:** General Usage\
**Tags:** question\
**Created:** [October 23, 2022, 10:38pm UTC](https://discourse.julialang.org/t/why-size-vector-2-return-1/89166 "2022-10-23T22:38:56Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![eliascarv](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/eliascarv/32/22152_2.png) [@eliascarv](https://discourse.julialang.org/u/eliascarv)\
**Post date:** [October 23, 2022, 10:38pm UTC](https://discourse.julialang.org/t/why-size-vector-2-return-1/89166/1 "2022-10-23T22:38:56Z")

</div>

I was wondering if there is a reason for this design decision.

Code example:

```julia-repl
julia> v = [1, 2, 3]
3-element Vector{Int64}:
 1
 2
 3

julia> size(v, 1)
3

julia> size(v, 2)
1

```

---

<div class="post-metadata">

**Author:** ![Palli](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/palli/32/3380_2.png) [@Palli](https://discourse.julialang.org/u/Palli)\
**Post date:** [October 23, 2022, 11:09pm UTC](https://discourse.julialang.org/t/why-size-vector-2-return-1/89166/2 "2022-10-23T23:09:42Z")

</div>

Even:

```julia
julia> size(v, 3) # etc. just do: size(v) to see "size" and number of dimensions.
1

```

I guess since it’s allowed by adding arbitrary many dimensions, to index like:

```julia
julia> v[2, 1, 1] # etc.

1

```

---

<div class="post-metadata">

**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [October 23, 2022, 11:31pm UTC](https://discourse.julialang.org/t/why-size-vector-2-return-1/89166/3 "2022-10-23T23:31:59Z")

</div>

> [@eliascarv](#):
>
> I was wondering if there is a reason for this design decision.

[https://docs.julialang.org/en/v1/manual/arrays/#Omitted-and-extra-indices](https://docs.julialang.org/en/v1/manual/arrays/#Omitted-and-extra-indices)

> Similarly, more than `N` indices may be provided if all the indices beyond the dimensionality of the array are 1 (or more generally are the first and only element of `axes(A, d)` where `d` is that particular dimension number). This allows vectors to be indexed like one-column matrices.