# What is \`N\` in \`Array{T,N}\`?

**URL:** <https://discourse.julialang.org/t/what-is-n-in-array-t-n/75476>\
**Category:** General Usage\
**Tags:** type, arrays\
**Created:** [January 30, 2022, 9:33pm UTC](https://discourse.julialang.org/t/what-is-n-in-array-t-n/75476 "2022-01-30T21:33:01Z")\
**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:** [January 30, 2022, 9:33pm UTC](https://discourse.julialang.org/t/what-is-n-in-array-t-n/75476/1 "2022-01-30T21:33:01Z")

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As in the title, what is `N` in `Array{T,N}` ?  
When dealing with parametric types, [the doc](https://docs.julialang.org/en/v1/manual/types/#Parametric-Types) shows the parameter being a _Type_, but here it is an integer.  
The doc actually says: " it can be any type at all (or a value of any bits type, actually, although here it’s clearly used as a type). Point{Float64} is…"

Is this the case?

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**Author:** ![Oscar\_Smith](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oscar_smith/32/25343_2.png) [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)\
**Post date:** [January 30, 2022, 9:39pm UTC](https://discourse.julialang.org/t/what-is-n-in-array-t-n/75476/2 "2022-01-30T21:39:24Z")

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It’s intended to be the number of dimensions (i.e. `1` for a `Vector`, `2` for `Matrix` etc). However, syntactically, you can make it whatever you want. `Array{Float64, 'q'}` is a valid type, even if you can’t instantiate it.

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [January 30, 2022, 9:58pm UTC](https://discourse.julialang.org/t/what-is-n-in-array-t-n/75476/3 "2022-01-30T21:58:00Z")

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> [@sylvaticus](#):
>
> a value of any bits type

That’s what you have here. For `Array{T,N}`, the parameter `N` is the value of a bits type (an `Int` value), indicating the **dimensionality of the array**.