python - Pandas 数据框中的计数和计数

Question

我有一个看起来像这样的 DF:

trainee | course | completed | days overdue
Ava       ABC      Yes         0
Bob       ABC      Yes         1
Charlie   DEF      No          10
David     DEF      Yes         0
Emily     DEF      Yes         0
Finn      GHI      Yes         0

我需要创建一个 DF，它会告诉我有多少门类(class)已上完，有多少是及时上完的(即 0 逾期天数)，以及完成的百分比是多少。

即结果应该是这样的:

course | count | in time | % completed in time
ABC      2       1         0.5
DEF      3       2         0.66
GHI      1       1         1

我怎样才能用 Pandas 做到这一点？

谢谢!

计划书

附注这是生成输入 DF 的代码:

df = pd.DataFrame({'Trainee': ['Ava','Bob','Charlie','David','Emily','Finn'],'Course':['ABC','ABC','DEF','DEF','DEF','GHI'],'Completed': ['Yes','Yes','No','Yes','Yes','Yes'],'Days overdue':[0,1,10,0,0,0]})

Answer 1

使用agg fot total and count 0 每组，最后将列除以 div :

tups = [('count', 'size'), ('in time', lambda x: (x==0).sum())]
df = df.groupby('course')['days overdue'].agg(tups).reset_index()

df['% completed in time'] = df['in time'].div(df['count'])
print (df)
  course  count  in time  % completed in time
0    ABC      2        1             0.500000
1    DEF      3        2             0.666667
2    GHI      1        1             1.000000