# What is it \`a = Array{Int64,1}\`?

**URL:** <https://discourse.julialang.org/t/what-is-it-a-array-int64-1/6494>\
**Category:** New to Julia\
**Tags:** array\
**Created:** [October 17, 2017, 9:15am UTC](https://discourse.julialang.org/t/what-is-it-a-array-int64-1/6494 "2017-10-17T09:15:27Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sylvaticus](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sylvaticus/32/203883_2.png) [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Post date:** [October 17, 2017, 9:15am UTC](https://discourse.julialang.org/t/what-is-it-a-array-int64-1/6494/1 "2017-10-17T09:15:27Z")

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Hello, what is it `a = Array{Int64,1}` ?  
In Juno I have the output `Vector{Int64}` and then if I `typeof(a)` I got `DataType`, put I can’t extend it, e.g. I can’t push!() over it.

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**Author:** ![fredrikekre](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/fredrikekre/32/1688_2.png) [@fredrikekre](https://discourse.julialang.org/u/fredrikekre)\
**Post date:** [October 17, 2017, 9:20am UTC](https://discourse.julialang.org/t/what-is-it-a-array-int64-1/6494/2 "2017-10-17T09:20:08Z")

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`Vector{T}` is just an alias for `Array{T,1}`, i.e. a one-dimensional `Array` with element type `T`. When you do

> [@sylvaticus](#):
>
> a = Array{Int64,1}

you assign the _type_ `Array{Int64,1}` to `a`, and the type of a type is `DataType`. I suspect you want an empty vector? In that case you have to call the constructor, i.e. `a = Vector{Int}()`. Note the parens.

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<div class="post-metadata">

**Author:** ![sylvaticus](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sylvaticus/32/203883_2.png) [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Post date:** [October 17, 2017, 9:21am UTC](https://discourse.julialang.org/t/what-is-it-a-array-int64-1/6494/3 "2017-10-17T09:21:20Z")

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got it… thank you…