# In Julia, how to create a function that saves its own internal state?

**URL:** <https://discourse.julialang.org/t/in-julia-how-to-create-a-function-that-saves-its-own-internal-state/58457>\
**Category:** New to Julia\
**Tags:** question, function\
**Created:** [April 2, 2021, 5:21pm UTC](https://discourse.julialang.org/t/in-julia-how-to-create-a-function-that-saves-its-own-internal-state/58457 "2021-04-02T17:21:33Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![pbayer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pbayer/32/11675_2.png) [@pbayer](https://discourse.julialang.org/u/pbayer)\
**Post date:** [April 2, 2021, 5:45pm UTC](https://discourse.julialang.org/t/in-julia-how-to-create-a-function-that-saves-its-own-internal-state/58457/4 "2021-04-02T17:45:10Z")

</div>

Use a closure:

```julia
julia> f(state=0) = ()->state+=1
f (generic function with 2 methods)

julia> foo = f()
#7 (generic function with 1 method)

julia> foo()
1

julia> foo()
2

julia> foo()
3

julia> foo.state
Core.Box(3)

julia> foo.state.contents
3

```

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