import pandas as pd
A = pd.DataFrame([[0,'a'],[1,'a'],[1,'a'],[1,'a'],[1,'a'],[0,'b'],[0,'b'],[1,'b'],[1,'b'],[1,'b'],[0,'c'],[0,'c']],
                 columns = ['Y','type'])
B = pd.DataFrame([['a',0.1],['b',0.2],['c',0.3]],
                columns = ['type','r'])
result = pd.merge(A,B,on = "type",how = "left")
result = result[['Y','r']]
print(result)