如何用大 pandas 删除除与某个值相对应的最大行以外的所有行? [英] How to remove all but the maximal row corresponding to some value with pandas?

问题描述

我有一个表，其中有诸如

I have a table with rows such as

df = pandas.DataFrame([[2001, "Jack", 77], [2005, "Jack", 44], [2001, "Jill", 93]],columns=['Year','Name','Value'])

    Year    Name    Value
0   2001    Jack    77
1   2005    Jack    44
2   2001    Jill    93

对于每个唯一的Name，我想保留具有最大Year值的行.在上面的示例中，我想要获取表

For each unique Name, I would like to keep the row with the largest Year value. In the above example I would like to get the table

    Year    Name    Value
0   2005    Jack    44
1   2001    Jill    93

这可以通过简单的方式完成吗?

Can this be done in a simple way?

推荐答案

df.drop_duplicates(subset = 'Name', keep = 'last')
    Year    Name    Value
1   2005    Jack    44
2   2001    Jill    93

像提到的@piRSquared一样编辑版本.

Writing an edited version just like @piRSquared mentioned.

df.sort_values('Year').drop_duplicates(subset = 'Name', keep = 'last')

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