pandas.core.groupby.DataFrameGroupBy.idxmin() 很慢，我怎样才能让我的代码更快？

Question

i am trying to do same action as SQL group by and take min value:

select id,min(value) ,other_fields...
from table
group by ('id')

i tried:

dfg = df.groupby('id', sort=False)
idx = dfg['value'].idxmin()
df = df.loc[idx, list(df.columns.values)]

https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.core.groupby.DataFrameGroupBy.idxmin.html but line 2 the idxmin() is taking more than half hour on ~4M columns in df where the group by takes less than 1 second, what am i missing is it suppose to take that long? how can make this process faster? will it be faster in pure SQL?

Answer 1

use alternative with DataFrame.sort_values and DataFrame.drop_duplicates :

df1 = df.sort_values(by=['value']).drop_duplicates('id', keep='first')