Rename ignoring not found

[chris-b1]

For the mapping overloads of rename / rename! - I've at times wanted to ignore columns that aren't found.

  rename(df::AbstractDataFrame, (from => to)::Pair...)
  rename(df::AbstractDataFrame, d::AbstractDict)
  rename(df::AbstractDataFrame, d::AbstractVector{<:Pair})

I think an optional kwarg would be a reasonable extension of the api? (not sure on name)

julia> df = DataFrame(; a=[1, 2, 3], b=[4, 5, 6])
3×2 DataFrame
 Row │ a      b
     │ Int64  Int64
─────┼──────────────
   1 │     1      4
   2 │     2      5
   3 │     3      6


julia> rename(df, :a => :column_1, :c => :column_2)
ERROR: ArgumentError: Tried renaming :c to :column_2, when :c does not exist in the Index.

julia> rename(df, :a => :column_1, :c => :column_2; ignorenotfound=true)
3×2 DataFrame
 Row │ column_1  b
     │ Int64     Int64
─────┼─────────────────
   1 │        1      4
   2 │        2      5
   3 │        3      6

[bkamins]

This issue pops up occasionally for several functions (I would need to think to create a list of them). We can consider adding it, as I can see the rationale (I understand you e.g. have many data frames with different column names and have a fixed set of operations you want to do and sometimes these operations do not apply as the data frame does not have some column - right?)

[chris-b1]

Thanks. Yep, in particular for me it is a messy data / evolving schema situation.

E.g., data from Jan-Feb has columns [:a, :b, :c], data from Mar has [:a, :b, :c, :d] and so on - I'd like one data processing pipeline that can handle any of the historical files.