# \`maximum\` element across the 2nd dim of a matrix with \`missing\` values

**URL:** <https://discourse.julialang.org/t/maximum-element-across-the-2nd-dim-of-a-matrix-with-missing-values/31463>\
**Category:** General Usage\
**Tags:** error\
**Created:** [November 24, 2019, 8:57pm UTC](https://discourse.julialang.org/t/maximum-element-across-the-2nd-dim-of-a-matrix-with-missing-values/31463 "2019-11-24T20:57:46Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![mroavi](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mroavi/32/8804_2.png) [@mroavi](https://discourse.julialang.org/u/mroavi)\
**Post date:** [November 24, 2019, 8:57pm UTC](https://discourse.julialang.org/t/maximum-element-across-the-2nd-dim-of-a-matrix-with-missing-values/31463/1 "2019-11-24T20:57:47Z")

</div>

I am trying to find the maximum element across the 2nd dim of a matrix with missing values.

This code unfortunatelly gives an error:

```julia
A = [1 missing 3; 4 5 missing; 7 8 9]
B = maximum(skipmissing(A), dims=2)

```

```julia
ERROR: LoadError: MethodError: no method matching
maximum(::Base.SkipMissing{Array{Union{Missing, Int64},2}}; dims=2)

```

My questions is: shouldn’t this work?

I found another way of doing it but is not as clean:

```julia
B = [maximum(skipmissing(row)) for row in eachrow(A)]

```

---

<div class="post-metadata">

**Author:** ![oheil](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oheil/32/220745_2.png) [@oheil](https://discourse.julialang.org/u/oheil)\
**Post date:** [November 24, 2019, 9:10pm UTC](https://discourse.julialang.org/t/maximum-element-across-the-2nd-dim-of-a-matrix-with-missing-values/31463/2 "2019-11-24T21:10:43Z")

</div>

```julia
help?> skipmissing
...
Note that even if itr is a multidimensional array, the result will always be a
  Vector since it is not possible to remove missings while preserving dimensions of the input.
...

```

So after skipmissing, there is no dimension 2 left.  
Thats probably why

```julia
maximum(::Base.SkipMissing{Array{Int64,2}}; dims=2)

```

has not been implemented

---

<div class="post-metadata">

**Author:** ![oheil](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/oheil/32/220745_2.png) [@oheil](https://discourse.julialang.org/u/oheil)\
**Post date:** [November 24, 2019, 9:16pm UTC](https://discourse.julialang.org/t/maximum-element-across-the-2nd-dim-of-a-matrix-with-missing-values/31463/3 "2019-11-24T21:16:31Z")

</div>

Actualy I think your solution is very clean!