根据中间数据框删除行

Question

df = 

freq     id
  11      a
  11      b
  10      c
  9       d
  1       e
  1       f

我想查看freq的每个值存储多少次，如果记录一次，请将其删除。 所需的输出：

  count = 

freq     recordings
  11      2
  10      1
   9      1
   1      2

然后

df = 

freq     id
  11      a
  11      b
   1      e 
   1      f

Answer 1

根据您的逻辑，您不会在输出中将10作为freq，因为它只出现一次：

df[df.groupby('freq')['freq'].transform('count').ne(1)] #change to .gt() for greater than 1

---

    freq id
0    11  a
1    11  b
4     1  e
5     1  f

Answer 2

IIUC duplicated

df=df[df.freq.duplicated(keep=False)].copy() # add copy for prevent the future copy warning 
   freq id
0    11  a
1    11  b
4     1  e
5     1  f