# How to use findmax!?

**URL:** https://discourse.julialang.org/t/how-to-use-findmax/83723
**Category:** General Usage
**Created:** [July 4, 2022, 7:41am UTC](https://discourse.julialang.org/t/how-to-use-findmax/83723 "2022-07-04T07:41:26Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![Raymond](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/raymond/32/36557_2.png) [@Raymond](https://discourse.julialang.org/u/Raymond)
#### Post date: [July 4, 2022, 7:41am UTC](https://discourse.julialang.org/t/how-to-use-findmax/83723/1 "2022-07-04T07:41:26Z")

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Dear all,

Can you give me an example of how to use `findmax!`?

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### Author: ![lawless-m](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lawless-m/32/30869_2.png) [@lawless-m](https://discourse.julialang.org/u/lawless-m)
#### Post date: [July 4, 2022, 7:59am UTC](https://discourse.julialang.org/t/how-to-use-findmax/83723/2 "2022-07-04T07:59:56Z")

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> [@Raymond](#):
>
> findmax!

I don’t know much about it myself but you can look at the unit tests

> <https://github.com/JuliaLang/julia/blob/742b9abb4dd4621b667ec5bb3434b8b3602f96fd/test/reducedim.jl#L213-L221>

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<div class="post-metadata">

### Author: ![jishnub](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jishnub/32/33620_2.png) [@jishnub](https://discourse.julialang.org/u/jishnub)
#### Post date: [July 4, 2022, 8:47am UTC](https://discourse.julialang.org/t/how-to-use-findmax/83723/3 "2022-07-04T08:47:53Z")

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```julia
julia> rval = zeros(); rind = zeros(Int);

julia> findmax!(rval, rind, [1:5; 4:-1:1])
(fill(5.0), fill(5))

julia> rval
0-dimensional Array{Float64, 0}:
5.0

julia> rind
0-dimensional Array{Int64, 0}:
5

```

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<div class="post-metadata">

### Author: ![Raymond](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/raymond/32/36557_2.png) [@Raymond](https://discourse.julialang.org/u/Raymond)
#### Post date: [July 4, 2022, 9:03am UTC](https://discourse.julialang.org/t/how-to-use-findmax/83723/4 "2022-07-04T09:03:21Z")

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Thanks, This is helpful to me.