About this question
Here is how I encountered the error:
df.loc[a_list][df.a_col.isnull()]The type of a_list is Int64Index， it contains a list of row indexes. All of these row indexes belong to df.
The df.a_col.isnull() part is a condition I need for filtering.
If I execute the following commands individually, I do not get any warnings:
df.loc[a_list]
df[df.a_col.isnull()]
But if I put them together df.loc[a_list][df.a_col.isnull()], I get the warning message (but I can see the result):
Boolean Series key will be reindexed to match DataFrame index
What is the meaning of this error message “userwarning: boolean series key will be reindexed to match dataframe index”? Does it affect the result that is returned?
