# Delete!() row from DataFrame incompatible with CSV.jl?

**URL:** <https://discourse.julialang.org/t/delete-row-from-dataframe-incompatible-with-csv-jl/39835>\
**Category:** Data\
**Tags:** dataframes, csv\
**Created:** [May 20, 2020, 2:18pm UTC](https://discourse.julialang.org/t/delete-row-from-dataframe-incompatible-with-csv-jl/39835 "2020-05-20T14:18:05Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Fred](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/fred/32/14175_2.png) [@Fred](https://discourse.julialang.org/u/Fred)\
**Post date:** [May 20, 2020, 2:18pm UTC](https://discourse.julialang.org/t/delete-row-from-dataframe-incompatible-with-csv-jl/39835/1 "2020-05-20T14:18:05Z")

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Hi !

Following some packages updates, the functions I add used to delete rows in dataframes, such as deleterows!(), have been deprecated and I try to make my old code running again but I face a difficult problem.

When a dataframe is read with the CSV package, I don’t find any solution to remove rows (except of course make a copy line by line of the lines I want to keep). If you have a simple solution for this, it will be helpful.  
Thanks !

```julia

julia> d = DataFrame(A=["X", "Y", "Z"], a=1:3, b=4:6)
3×3 DataFrame
│ Row │ A │ a │ b │
│ │ String │ Int64 │ Int64 │
├─────┼────────┼───────┼───────┤
│ 1 │ X │ 1 │ 4 │
│ 2 │ Y │ 2 │ 5 │
│ 3 │ Z │ 3 │ 6 │

julia> delete!(d, 2) # it works !
2×3 DataFrame
│ Row │ A │ a │ b │
│ │ String │ Int64 │ Int64 │
├─────┼────────┼───────┼───────┤
│ 1 │ X │ 1 │ 4 │
│ 2 │ Z │ 3 │ 6 │

julia> d = DataFrame(A=["X", "Y", "Z"], a=1:3, b=4:6)
3×3 DataFrame
│ Row │ A │ a │ b │
│ │ String │ Int64 │ Int64 │
├─────┼────────┼───────┼───────┤
│ 1 │ X │ 1 │ 4 │
│ 2 │ Y │ 2 │ 5 │
│ 3 │ Z │ 3 │ 6 │

julia> CSV.write("test.csv", d ; delim = "\t")
"test.csv"

julia> d = CSV.read("test.csv")
3×3 DataFrame
│ Row │ A │ a │ b │
│ │ String │ Int64 │ Int64 │
├─────┼────────┼───────┼───────┤
│ 1 │ X │ 1 │ 4 │
│ 2 │ Y │ 2 │ 5 │
│ 3 │ Z │ 3 │ 6 │

julia> delete!(d, 2) # same function, same dataframe, it does not work !
ERROR: MethodError: no method matching deleteat!(::CSV.Column{String,String}, ::Int64)
Closest candidates are:
  deleteat!(::Array{T,1} where T, ::Integer) at array.jl:1238
  deleteat!(::Array{T,1} where T, ::Any) at array.jl:1275
  deleteat!(::BitArray{1}, ::Integer) at bitarray.jl:931
  ...
Stacktrace:
 [1] (::DataFrames.var"#161#162"{Int64})(::CSV.Column{String,String}) at /home/fred/.julia/packages/DataFrames/3ZmR2/src/dataframe/dataframe.jl:873
 [2] foreach(::DataFrames.var"#161#162"{Int64}, ::Array{AbstractArray{T,1} where T,1}) at ./abstractarray.jl:1919
 [3] delete!(::DataFrame, ::Int64) at /home/fred/.julia/packages/DataFrames/3ZmR2/src/dataframe/dataframe.jl:873
 [4] top-level scope at REPL[25]:1

```

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<div class="post-metadata">

**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:** [May 20, 2020, 2:23pm UTC](https://discourse.julialang.org/t/delete-row-from-dataframe-incompatible-with-csv-jl/39835/2 "2020-05-20T14:23:17Z")

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Please do not use `CSV.read` as it will be soon deprecated. Instead use `DataFrame(CSV.File(filename, ...))` and all will work as expected.

This is problem is with CSV.jl and is not related with DataFrames.jl.

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<div class="post-metadata">

**Author:** ![Fred](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/fred/32/14175_2.png) [@Fred](https://discourse.julialang.org/u/Fred)\
**Post date:** [May 20, 2020, 2:28pm UTC](https://discourse.julialang.org/t/delete-row-from-dataframe-incompatible-with-csv-jl/39835/3 "2020-05-20T14:28:28Z")

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@bkamins thank you for your quick answer and solution that indeed works ! The bad news is that I have used `CSV.read` massively in the past in most of my Julia programs ☹

```julia
julia> d = DataFrame(CSV.File("test.csv"; delim = "\t"))
3×3 DataFrame
│ Row │ A │ a │ b │
│ │ String │ Int64 │ Int64 │
├─────┼────────┼───────┼───────┤
│ 1 │ X │ 1 │ 4 │
│ 2 │ Y │ 2 │ 5 │
│ 3 │ Z │ 3 │ 6 │

julia> delete!(d, 2)
2×3 DataFrame
│ Row │ A │ a │ b │
│ │ String │ Int64 │ Int64 │
├─────┼────────┼───────┼───────┤
│ 1 │ X │ 1 │ 4 │
│ 2 │ Z │ 3 │ 6 │

```

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<div class="post-metadata">

**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:** [May 20, 2020, 2:43pm UTC](https://discourse.julialang.org/t/delete-row-from-dataframe-incompatible-with-csv-jl/39835/4 "2020-05-20T14:43:59Z")

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> [@Fred](#):
>
> `CSV.read`

This will allow CSV.jl not to have DataFrames.jl as a dependency.  
Maybe @quinnj will want to comment on this more.