Python数据表：sum，groupby，列< 0 [英] Python datatable: sum, groupby, column < 0

问题描述

我正在努力将一些R代码转换为Python代码。

Hi I am struggling to translate some R code into Python code.

这是我的R代码：

  df_sum <- df[, .(
    Inflow = sum(subset(Amount, Amount>0)),
    Outflow = sum(subset(Amount, Amount<0)),
    Net = sum(Amount)
  ), by = Account]

这是我到目前为止的Python代码：

This is my Python code so far:

df_sub = df[:, {'Inflow': dt.sum(dt.f.Amount),
                'Outflow': dt.sum(dt.f.Amount),
                'Net': dt.sum(dt.f.Amount)},
         dt.by('Account')]

我不知道如何包括流入和流出列的子集。有人可以帮忙吗？

I don't know how to include the subset for the inflow and outflow columns. Can anyone help?

这是所需的输出（使用R代码生成）：

This is the desired output (generated with R code):

     Account Inflow Outflow  Net
1: Account 1    151     -32  119
2: Account 2     51    -226 -175

示例数据：

{'Account': ['Account 1', 'Account 1', 'Account 1', 'Account 1', 'Account 1', 'Account 1', 'Account 1', 'Account 1', 'Account 1', 'Account 2', 'Account 2', 'Account 2', 'Account 2', 'Account 2', 'Account 2', 'Account 2', 'Account 2', 'Account 2'], 'Amount': [34, 23, -23, -4, 34, 4, -3, 56, -2, 3, 5, 43, -67, -3, -78, -7, -4, -67]}

推荐答案

使用 ifelse 函数复制R代码：

from datatable import dt, f, by, ifelse

   df[:, {"Inflow": dt.sum(ifelse(f.Amount > 0, f.Amount, None)),
          "Outflow": dt.sum(ifelse(f.Amount < 0, f.Amount, None )),
          "Net": dt.sum(f.Amount)}, 
      by("Account")]

     Account    Inflow  Outflow Net
0   Account1       151   −32    119
1   Account2        51   −226  −175

这篇关于Python数据表：sum，groupby，列< 0的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！