# Error: create a column from an existing array

**URL:** <https://discourse.julialang.org/t/error-create-a-column-from-an-existing-array/43411>\
**Category:** New to Julia\
**Tags:** question, dataframes\
**Created:** [July 21, 2020, 3:26am UTC](https://discourse.julialang.org/t/error-create-a-column-from-an-existing-array/43411 "2020-07-21T03:26:48Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![PabloGalaz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pablogalaz/32/16281_2.png) [@PabloGalaz](https://discourse.julialang.org/u/PabloGalaz)\
**Post date:** [July 21, 2020, 3:26am UTC](https://discourse.julialang.org/t/error-create-a-column-from-an-existing-array/43411/1 "2020-07-21T03:26:48Z")

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Hello everyone,

I’m trying to add a new column (in the first position) to an existing DataFrame (df) from an existing array (members) but when I run `insertcols!(df,1, :Members =>members)`, it show me following error:

```julia
ArgumentError: adding AbstractArray other than AbstractVector as a column of a data frame is not allowed

Stacktrace:
 [1] insertcols!(::DataFrame, ::Int64, ::Pair{Symbol,Array{String,2}}; makeunique::Bool, copycols::Bool) at /Users/pablogalaz/.julia/packages/DataFrames/kwVTY/src/dataframe/dataframe.jl:760
 [2] insertcols!(::DataFrame, ::Int64, ::Pair{Symbol,Array{String,2}}) at /Users/pablogalaz/.julia/packages/DataFrames/kwVTY/src/dataframe/dataframe.jl:721
 [3] top-level scope at In[44]:1

```

I already try to do this with other df-array and it works very well. The rest of the code here:

```julia
members = ["Belen" "Lau" "Javi" "Joaco" "Nico" "Rodrigo" "Vicente" "Pablo" "Falcao" "Montse"]

df = 
Row	Lunes	Martes	Miercoles	Jueves	Viernes	Sabado	Domingo
    Int64	Int64	Int64 Int64	Int64	Int64	Int64
1	0 0 1 0 0 -1 -1
2	1 0 0 0 1 -1 -1
3	0 0 1 -1 0 -1 1
4	1 0 0 1 1 -1 -1
5	1 1 0 -1 0 1 -1
6	0 1 0 -1 1 1 -1
7	0 1 0 -1 1 -1 1
8	1 1 0 1 0 -1 -1
9	0 0 1 1 -1 1 -1
10	0 0 1 1 -1 -1 1

insertcols!(df,1, :Members =>members) #ERROR

```

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<div class="post-metadata">

**Author:** ![longemen3000](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/longemen3000/32/7298_2.png) [@longemen3000](https://discourse.julialang.org/u/longemen3000)\
**Post date:** [July 21, 2020, 3:43am UTC](https://discourse.julialang.org/t/error-create-a-column-from-an-existing-array/43411/2 "2020-07-21T03:43:20Z")

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> [@PabloGalaz](#):
>
> `members = ["Belen" "Lau" "Javi" "Joaco" "Nico" "Rodrigo" "Vicente" "Pablo" "Falcao" "Montse"]`

it worked when i added commas between the strings:

```julia
using DataFrames
df = dataframe(a = rand(10))  
members = ["Belen","Lau","Javi","Joaco","Nico","Rodrigo","Vicente","Pablo","Falcao","Montse"]
julia> insertcols!(df,1, :Members =>members)
10×2 DataFrame
│ Row │ Members │ a │        
│ │ String │ Float64 │        
├─────┼─────────┼───────────┤
│ 1 │ Belen │ 0.5535 │        
│ 2 │ Lau │ 0.696888 │
│ 3 │ Javi │ 0.285581 │        
│ 4 │ Joaco │ 0.503806 │        
│ 5 │ Nico │ 0.305051 │        
│ 6 │ Rodrigo │ 0.0708788 │        
│ 7 │ Vicente │ 0.268658 │
│ 8 │ Pablo │ 0.14032 │        
│ 9 │ Falcao │ 0.517392 │        
│ 10 │ Montse │ 0.264026 │        

```

the problem seems to stem from the fact that you were trying to add a row of names as it was a column. but adding the commas solves the problem.  
Other option,that works for your original input:

```julia
insertcols!(df,1, :Members =>vec(members)) #reinterprets the Array as a vector

```

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<div class="post-metadata">

**Author:** ![PabloGalaz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pablogalaz/32/16281_2.png) [@PabloGalaz](https://discourse.julialang.org/u/PabloGalaz)\
**Post date:** [July 21, 2020, 4:17pm UTC](https://discourse.julialang.org/t/error-create-a-column-from-an-existing-array/43411/3 "2020-07-21T16:17:13Z")

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The vec() function was the solve! Thank you