GroupBy.apply(func, *args, **kwargs)[source]
Apply function func group-wise and combine the results together.
The function passed to apply must take a dataframe as its...
一、先准备要使用的类:
1、person类:
class person
{
public string name { set; get; }
public int age { set; get; }
public string gender { set; get; }
public override string tostri...