python - 显示没有重复值的列的总数

Question

我有一个脚本可以输出一个包含五列的 csv。我添加了两行代码来对其中两列求和。我设法做到了这一点，但是，总计是这些列在每一行上重复，我只希望总计显示在一行上。

df['Unit Total'] = df['Units Sold'].sum()
df['Total Revenue'] = df['data_revenue'].sum()

这是我的脚本产生的结果

8   0.013207    AR  ARS 0.105656    74012   575.2779
10  0.013207    AR  ARS 0.13207     74012   575.2779
6   0.013207    AR  ARS 0.079242    74012   575.2779
6   0.013207    AR  ARS 0.079242    74012   575.2779

我真正想看到的

8   0.013207    AR  ARS 0.105656    74012   575.2779
10  0.013207    AR  ARS 0.13207     
6   0.013207    AR  ARS 0.079242    
6   0.013207    AR  ARS 0.079242    

我的脚本

for filename in filelist:
    print(filename)
    df = pandas.read_csv('SYB_M_20171001_20171031.txt', header=None, encoding='utf-8', sep='\t', names=colnames,
                         skiprows=3, usecols=['Units Sold', 'Dealer Price', 'End Consumer Country', 'Currency Code']
                         )
    df['data_revenue'] = df['Units Sold'] * df['Dealer Price']
    df = df.sort_values(['End Consumer Country', 'Currency Code'])
    df['Unit Total'] = df['Units Sold'].sum()
    df['Total Revenue'] = df['data_revenue'].sum()
    df.to_csv(outfile + r"\output.csv", index=None)
    dflist.append(filename)

Answer 1

按位置设置索引的第一个值:

df.loc[df.index[0], 'Unit Total'] = df['Units Sold'].sum()

df.loc[df.index[0], 'Unit Revenue'] = df['data_revenue'].sum()

另一种解决方案是通过 reset_index 创建默认索引使用 drop=True，因此可能由 0 设置:

df = df.sort_values(['End Consumer Country', 'Currency Code']).reset_index(drop=True)

df.loc[0, 'Unit Total'] = df['Units Sold'].sum()
df.loc[0, 'Unit Revenue'] = df['data_revenue'].sum()