Search (row values) data from another dataframe - python-3.x

Question

I have two dataframes, df1 and df2 respectively.
In one dataframe I have a list of search values (Actually Col1)
Col1 Col2
A1 val1, val2
B2 val4, val1
C3 val2, val5
I have another dataframe where I have a list of items
value items
val1 apples, oranges
val2 honey, mustard
val3 banana, milk
val4 biscuit
val5 chocolate
I want to iterate though the first DF and try to use that val as key to search for items from the second DF
Expected output:
A1 apples, oranges, honey, mustard
B2 biscuit, appleas, oranges
C3 honey, mustard, chocolate
I am able to add the values into dataframe and iterate through 1st DF
for index, row in DF1:
#list to hold all the values
finalList = []
list = df1['col2'].split(',')
for i in list:
print(i)
I just need help to fetch values from the second dataframe.
Would appreciate any help. Thanks.

Answer 1

Idea is use lambda function with split and lookup by dictionary:
d = df2.set_index('value')['items'].to_dict()
df1['Col2'] = df1['Col2'].apply(lambda x: ', '.join(d[y] for y in x.split(', ') if y in d))
print (df1)
Col1 Col2
0 A1 apples, oranges, honey, mustard
1 B2 biscuit, apples, oranges
2 C3 honey, mustard, chocolate
If there are lists in items values solution is changed with flattening:
d = df2.set_index('value')['items'].to_dict()
f = lambda x: ', '.join(z for y in x.split(', ') if y in d for z in d[y])
df1['Col2'] = df1['Col2'].apply(f)
print (df1)
Col1 Col2
0 A1 apples, oranges
1 B2 biscuit, apples, oranges
2 C3 honey, mustard, chocolate