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Questions - dataframes.jl

Split a DataFrame into a Vector of DataFrames

I have a DataFrame df = DataFrame(a=[1,1,2,2],b=[6,7,8,9]) 4×2 DataFrame Row │ a b │ Int64 Int64 ─────┼────────────── 1 │ 1 6 2 │ 1 7 3 │ 2 8 ...
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Georgery

dataframe

julia

dataframes.jl

Votes: 0

Answers: 1

Latest Answer

Use: julia> gdf = groupby(df, :a, sort=true) GroupedDataFrame with 2 groups based on key: a First Group (2 rows): a = 1 Row │ a b │ Int64 Int64 ─────┼────────────── 1 │ 1 6 ...
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Bogumił Kamiński

Writing function methods for passing GroupedDataFrame in Julia

I have written a function like the following one: gini(v::Array{<:Real,1}) = (2 * sum([x*i for (i,x) in enumerate(sort(v))]) / sum(sort(v)) - (length(v)+1))/(length(v)) This function works well wh...
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Josep Espasa

julia

dataframes.jl

Votes: 0

Answers: 1

Latest Answer

You need to change method signature to: gini(v::AbstractVector{<:Real}) The point is that combine passes a view of a vector (which does not have Vector type but SubArray). Therefore you need to al...
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Bogumił Kamiński

How to prevent Columns from being Decimals in DataFrames when retrieved from Postgres

I have a DataFrame df which I retrieved from a Postgres database as follows using DataFrames, LibPQ con = LibPQ.Connection(con_string) result = execute(con, "SELECT * FROM [table]") df = Da...
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Georgery

dataframe

julia

libpq

dataframes.jl

Votes: 0

Answers: 2

Latest Answer

You can use Union{Missing, AbstractFloat} as type selector as Decimal <: AbstractFloat. Since Union{Missing, AbstractFloat} is not a concrete type you need to write eltype(col) <: Union{Missing,...
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Bogumił Kamiński

Sort Julia DataFrame in descending Order

I have a DataFrame using DataFrames using DataFramesMeta using Chain df = DataFrame(a=1:3,b=4:6) that I want to sort descending by column :a. Doing it ascending is intuitive... @chain df begin @...
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Georgery

dataframe

julia

dataframes.jl

dataframesmeta.jl

Votes: 0

Answers: 2

Latest Answer

So, if you have a numeric column, you can simply negate it... using DataFrames using DataFramesMeta using Chain df = DataFrame(a=1:3,b=4:6) @chain df begin @orderby(-:a) end But this logic does...
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Georgery

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