我正在处理一个大型csv文件,该文件具有看起来像这样的信息
id year decade code type
3366 2014 2010 EM Chemical
3366 2014 2010 EM Chemical
3366 2014 2010 EM Chemical
3366 2014 2010 EM Chemical
3366 2014 2010 EM Chemical
427 1972 1970 DR Coastal Storm
337 1972 1970 DR Coastal Storm
337 1972 1970 DR Coastal Storm
我想按“ id”列中唯一身份出现的次数进行排序。我想要的结果看起来像
id year decade code type count
3366 2014 2010 EM Chemical 5
427 1972 1970 DR Coastal Storm 1
337 1972 1970 DR Coastal Storm 2
但是我试图解决类似问题
id year decade code type count
3366 2014 2010 EM Chemical 5
3366 2014 2010 EM Chemical 5
3366 2014 2010 EM Chemical 5
3366 2014 2010 EM Chemical 5
3366 2014 2010 EM Chemical 5
427 1972 1970 DR Coastal Storm 1
337 1972 1970 DR Coastal Storm 1
337 1972 1970 DR Coastal Storm 2
我尝试通过尝试做到这一点
df['count']=df.groupby('id').transform('count')
但是我总是收到错误消息
ValueError: Wrong number of items passed 18,placement implies 1
是否有更好的方法来实现这一目标?