# UndefVarError: categorical! in Julia

**URL:** <https://discourse.julialang.org/t/undefvarerror-categorical-in-julia/97160>\
**Category:** New to Julia\
**Tags:** question, dataframes\
**Created:** [April 6, 2023, 9:16am UTC](https://discourse.julialang.org/t/undefvarerror-categorical-in-julia/97160 "2023-04-06T09:16:41Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![nirong](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nirong/32/48859_2.png) [@nirong](https://discourse.julialang.org/u/nirong)\
**Post date:** [April 6, 2023, 9:16am UTC](https://discourse.julialang.org/t/undefvarerror-categorical-in-julia/97160/1 "2023-04-06T09:16:41Z")

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i am using julia version1.8.5. I define a variable "geordd\_df“ with DataFrame function. There is a ”UndefVarError: categorical! not defined“ when i run “categorical!(geordd\_df, :categ)” in julia

 ![fig4](https://global.discourse-cdn.com/julialang/original/3X/c/1/c12c0d96f4db6ad9dcf757f9ae6793ea70c67e63.png)  
. can anyone help?

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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:** [April 6, 2023, 9:33am UTC](https://discourse.julialang.org/t/undefvarerror-categorical-in-julia/97160/2 "2023-04-06T09:33:17Z")

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The reason you get this error is that there is no `categorical!` function defined.

You can do e.g.:

```julia
using CategoricalArrays
geordd_df.categ = categorical(geordd_df.categ)

```

or

```julia
using CategoricalArrays
transform!(geordd_df, :categ => categorical => :categ)

```

instead

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<div class="post-metadata">

**Author:** ![nirong](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nirong/32/48859_2.png) [@nirong](https://discourse.julialang.org/u/nirong)\
**Post date:** [April 6, 2023, 10:09am UTC](https://discourse.julialang.org/t/undefvarerror-categorical-in-julia/97160/3 "2023-04-06T10:09:28Z")

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@bkamins Thanks a lot for your quick response. The second method works well.