在朱莉娅中的总和，如R或熊猫

Question

我想按季度频率汇总一个月序列，其中R有ts和aggregate() (参见the first answer on this thread)，pandas有df.resample("Q").sum() (参见this question)。朱莉娅也提供类似的东西吗？

附录:我目前的解决方案使用一个函数将数据转换为第一季度和拆分应用-合并：

"""
    month_to_quarter(date)

Returns the date corresponding to the first day of the quarter enclosing date

# Examples
```jldoctest

julia> Date(1990，1，1) == RED.month_to_quarter(日期(1990，2，1))

真的

julia> Date(1990，1，1) == RED.month_to_quarter(日期(1990，1，1))

真的

julia> Date(1990，1，1) == RED.month_to_quarter(日期(1990，2，25))

真的

"""
function month_to_quarter(date::Date)
    new_month = 1 + 3 * floor((Dates.month(date) - 1) / 3)
    return Date(Dates.year(date), new_month, 1)
end


""" 
    monthly_to_quarterly(monthly_df)

Aggregates a monthly data frame to the quarterly frequency. The data frame should have a :DATE column.

# Examples
```jldoctest

julia>月=转换(DataFrame，hcat(Dates.Date(1990，m，1) in 1:3)，1；2；3)；

julia>重命名！(每月，:x1 => :DATE)；

julia>重命名！(每月，:x2 => :value)；

julia>季刊=RED.monthly_to_quarterly(月)；

julia>季刊:价值

2.0

julia>长度(季度:值)

1

"""
function monthly_to_quarterly(monthly::DataFrame)

    # quarter months: 1, 4, 7, 10
    quarter_months = collect(1:3:10)

    # Deep copy the data frame
    monthly_copy = deepcopy(monthly)

    # Drop initial rows until it starts on a quarter
    while !in(Dates.month(monthly_copy[:DATE][1]), quarter_months)

        # Verify that something is left to pop
        @assert 1 <= length(monthly_copy[:DATE])

        monthly_copy = monthly_copy[2:end, :]
    end

    # Drop end rows until it finishes before a quarter
    while !in(Dates.month(monthly_copy[:DATE][end]), 2 + quarter_months)
    monthly_copy = monthly_copy[1:end-1, :]
    end

    # Change month of each date to the nearest quarter
    monthly_copy[:DATE] = month_to_quarter.(monthly_copy[:DATE])

    # Split-apply-combine
    quarterly = by(monthly_copy, :DATE, df -> mean(df[:value]))

    # Rename
    rename!(quarterly, :x1 => :value)

    return quarterly

end

Answer 1

我在文档里找不到这样的功能。下面是您自己的答案的更多DataFrames.jl版本和更简洁的版本

using DataFrames
# copy-pasted your own function
function month_to_quarter(date::Date)
    new_month = 1 + 3 * floor((Dates.month(date) - 1) / 3)
    return Date(Dates.year(date), new_month, 1)
end

# the data
r=collect(1:6)
monthly = DataFrame(date=[Dates.Date(1990, m, 1) for m in r], 
            val=r);

# the functionality
monthly[:quarters] = month_to_quarter.(monthly[:date])
_aggregated = by(monthly, :quarters, df -> DataFrame(S = sum(df[:val])))

@show monthly
@show _aggregated