How to filter a dataframe by rows of another one?

Question

I have two dataframes: df1:

 id          type
"a"      "alpha"
"a"      "alpha"
"a"      "beta"
"a"      "gamma"

and df2:

 id          type          
"a"      "alpha"         
"a"      "alpha"         
"a"      "alpha"          
"a"      "alpha"          
"a"      "beta"           
"a"      "beta"

for each row in df1 i want to remove single row from df2 if they have same "id" and "type". so desired result is:

 id          type          
"a"      "alpha"         
"a"      "alpha"          
"a"      "beta"

How could I do that?

Asked By: Ir8_mind

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Source

Answer 1

You can use collection.Counter to subtract element of df1 from df2, then rebuild a Dataframe:

from collections import Counter
diff = Counter(zip(df2['id'], df2['type'])) - Counter(zip(df1['id'], df1['type']))
pd.DataFrame([k for k,v in diff.items() for _ in range(v)], columns=["id", "type"])

Output:

    id     type
0  "a"  "alpha"
1  "a"  "alpha"
2  "a"   "beta"

Answered By: Tranbi

How to filter a dataframe by rows of another one?

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