How to call a column in DataFrame that has a space in the name

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Got it, thank you so much! This clears up a lot.

I apologize for not making the reference clear. The quotes come from Strings vs symbols in DataFrames.jl column indexing. Given my inadequate background I completely misunderstood the well written post.

I took the following examples to mean that a DataFrame column label was being stored as either a symbol or a string and must then be indexed in accordance with the type with which it was created.

( This sent me down a rabbit hole as to why the columns in @sijo 's example here could be accessed with a string as the transform operation output NamedTuples as new columns. Which lead to the above post.)

Now my understanding is that no matter how I create the DataFrame Column, it is stored in one way (a symbol?), and can be indexed freely with both symbols and strings.

Sorry don’t mean to create so much confusion on the discussion board. @bkamins book came out on amazon today so I should have a better understanding of things going forward.

Strings vs symbols in DataFrames.jl

Column names in a DataFrame are labels. For this reason both symbols and strings are allowed to be used when referencing them without introducing an ambiguity. Here is an example. We start with strings:

julia> using DataFrames

julia> df = DataFrame("col1" => 1, "col 2" => 2)
1×2 DataFrame
 Row │ col1   col 2
     │ Int64  Int64
─────┼──────────────
   1 │     1      2

julia> df."col1"
1-element Vector{Int64}:
 1

julia> df."col 2"
1-element Vector{Int64}:
 2

julia> df[:, "col1"]
1-element Vector{Int64}:
 1

julia> df[:, "col 2"]
1-element Vector{Int64}:
 2

Now we try the same with symbols:

julia> df = DataFrame(:col1 => 1, Symbol("col 2") => 2)
1×2 DataFrame
 Row │ col1   col 2
     │ Int64  Int64
─────┼──────────────
   1 │     1      2

julia> df.col1
1-element Vector{Int64}:
 1

julia> getproperty(df, Symbol("col 2"))
1-element Vector{Int64}:
 2

julia> df[:, :col1]
1-element Vector{Int64}:
 1

julia> df[:, Symbol("col 2")]
1-element Vector{Int64}:
 2

We now see the first difference, that we have already discussed. If column names are all valid variable names symbols are more convenient, however, if they are not (e.g. contain spaces) then using strings is more convenient. As an extreme case, note that the convenience syntax for getproperty using. accessor does not work for symbols containing spaces and we need to do an explicit getproperty call.

But now I understand that all columns are stored the same way