pandas select Z6A8064B5DF4794555500553C47C55057DZ 行根据配对条件

Question

I have a dataframe like following:

df = pd.DataFrame({
    'contract':[11, 11, 11, 12, 12, 13, 13, 13, 13], 
    'num_date':[1, 2, 3, 1, 2, 1, 2, 3, 4],
    'val': [100, 110, 120, 50, 150, 95, 105, 115, 125]
})

Pairs (contracts, num_date) are unique

Also I have the list of tuples:

filt = [(11, 1),
        (11, 1),
        (12, 3),
        (12, 2),
        (13, 3),
        (13, 1)]

Each tuple in list is a pair (contract, num_date) for dataframe above.

I need choose rows from dataframe according to this list as a condition, and if the tuple is repeated several times then the row corresponding to it also must be repeated the same number of times.

For example for dataframe and list of tuples above solution is

contract	num_date	val
11	1	100
11	1	100
12	2	150
13	3	115
13	1	95

Will be better if the solution will be time-efficient

Answer 1

First you need to convert the tuples into a dataframe:

df2 = pd.DataFrame(filt)
df2.columns = ['contract', 'num_date']

Then merge between the two and drop nulls:

df2 = df2.merge(right=df, on = ['contract', 'num_date'], how='left')
df2.dropna(subset=['val'], inplace=True)