# Buglet? Warning on groupby

**URL:** https://discourse.julialang.org/t/buglet-warning-on-groupby/18390
**Category:** Data
**Created:** [December 6, 2018, 5:53pm UTC](https://discourse.julialang.org/t/buglet-warning-on-groupby/18390 "2018-12-06T17:53:12Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![iwelch](https://avatars.discourse-cdn.com/v4/letter/i/8c91f0/32.png) [@iwelch](https://discourse.julialang.org/u/iwelch)
#### Post date: [December 6, 2018, 5:53pm UTC](https://discourse.julialang.org/t/buglet-warning-on-groupby/18390/1 "2018-12-06T17:53:12Z")

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Is the Warning message a buglet?

```julia
julia> using DataFrames; df= DataFrame( n1=1:9, cat=['A','B','A', 'B','C','B', 'C','A','C'] );

julia> groupby(df, :cat)
GroupedDataFrame{DataFrame} with 3 groups based on key: :cat
First Group: 3 rows┌ Warning: iterating over value of eachcol on SubDataFrame will return a pair of column name and a view of column value
│ caller = ip:0x0
└ @ Core :-1

...[deleted]....

```

---

<div class="post-metadata">

### Author: ![pdeffebach](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pdeffebach/32/10320_2.png) [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)
#### Post date: [December 6, 2018, 5:58pm UTC](https://discourse.julialang.org/t/buglet-warning-on-groupby/18390/2 "2018-12-06T17:58:37Z")

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This deprecation warning will be fixed shortly, if it hasn’t already been fixed on master.

It has to do with the a recently changed behavior of `eachcol` motivated by consistency with a [new feature in base](https://github.com/JuliaData/DataFrames.jl/issues/1611#issuecomment-443150400).