# How to filter out missings (using DataFramesMeta @where)

**URL:** <https://discourse.julialang.org/t/how-to-filter-out-missings-using-dataframesmeta-where/26618>\
**Category:** New to Julia\
**Tags:** dataframes\
**Created:** [July 22, 2019, 6:18am UTC](https://discourse.julialang.org/t/how-to-filter-out-missings-using-dataframesmeta-where/26618 "2019-07-22T06:18:18Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![abeburnett](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abeburnett/32/8974_2.png) [@abeburnett](https://discourse.julialang.org/u/abeburnett)\
**Post date:** [July 22, 2019, 6:18am UTC](https://discourse.julialang.org/t/how-to-filter-out-missings-using-dataframesmeta-where/26618/1 "2019-07-22T06:18:18Z")

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How do I filter out missings when working with DataFramesMeta? For context, my background is R/Python, and in R I use the tidyverse/dplyr/etc. heavily.

I want to do:

```julia
@linq indeed_dice_data |>
    transform(mean_subdomain_all_freq_sma = mean(skipmissing([:subdomain_all_freq_sma, :subdomain_all_freq_sma_1]))) |>
    where(!ismissing.(:mean_subdomain_all_freq_sma)) |>
    select(:subdomain, :floor_month_date, :mean_subdomain_all_freq_sma)

```

But that doesn’t work… In R/dplyr it’d just be a filter(!is.na(blah\_blah\_blah)), so I’m curious how to do this simple operation in Julia. Still trying to figure out how to map everything I do in R to Julia, and I’m aware this is probably an uber easy question for most of you.

Thanks in advance!

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<div class="post-metadata">

**Author:** ![quinnj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/quinnj/32/11_2.png) [@quinnj](https://discourse.julialang.org/u/quinnj)\
**Post date:** [July 22, 2019, 11:38am UTC](https://discourse.julialang.org/t/how-to-filter-out-missings-using-dataframesmeta-where/26618/2 "2019-07-22T11:38:09Z")

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What’s the error you’re running into? It might just be a typo or something.

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**Author:** ![bkamins](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bkamins/32/208538_2.png) [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Post date:** [July 22, 2019, 11:43am UTC](https://discourse.julialang.org/t/how-to-filter-out-missings-using-dataframesmeta-where/26618/3 "2019-07-22T11:43:52Z")

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Use `dropmissing` function:

```julia
julia> df = DataFrame(a=[1, missing, 2], b=1:3)
3×2 DataFrame
│ Row │ a │ b │
│ │ Int64⍰ │ Int64 │
├─────┼─────────┼───────┤
│ 1 │ 1 │ 1 │
│ 2 │ missing │ 2 │
│ 3 │ 2 │ 3 │

julia> @linq df |> transform(d=2*:a) |> dropmissing(:a) |> select(:d, :b)
2×2 DataFrame
│ Row │ d │ b │
│ │ Int64⍰ │ Int64 │
├─────┼────────┼───────┤
│ 1 │ 2 │ 1 │
│ 2 │ 4 │ 3 │

```