Facing difficulty in python comparing instances of two class objects based on emp_id

Question

I am new to python and i am facing issues with comparing instances of class objects taken from csv files. I assigned the data of person.csv to class Employee and benefits.csv to class Benefits. Now, I need to comapre the instances of both the classes ie, (emp_id). Here are my two csv files: person.csv:

emp_id sex  age
1      Male  25
2     Female 26
3      Male   28

benefits.csv:

emp_id code type
1       A1  1
1       B20  2
1       A10  1
2       B20  2
3       A10  1
3       C2   2

code:

class Benefits():
  def __init__(self,emp_id,code,codetype):
    super().__init__()
    self.emp_id = emp_id
    self.code = code
    self.codetype = codetype

class Employee():
  def __init__(self,emp_id,sex,age):
    super().__init__()
    self.emp_id = emp_id
    self.sex = sex
    self.age = age
    self.benefits = []

    def __repr__(self): # specifies how to display an Employee
    return "EMP NO:" + str(self.emp_id) + ",SEX:" + str(self.sex) + ",AGE:" + str(self.age) + ",Benefits:" + str(self.benefits)

  def add_benefits(self,ben):
    self.benefits.append(ben)

dir = os.path.dirname(__file__)
file1 = open(os.path.join(dir,"person.csv"), 'r')
next(file1)
directory = os.path.dirname(__file__)
file2 = open(os.path.join(directory, "benefits.csv"), 'r')
next(file2)
  
for line1 in file1:
    vals1 = list(map(lambda s: s.strip(),line1.split(",")))
    E = Employee(vals1[0],vals1[1],vals1[2])
for line2 in file2:
    vals2 = list(map(lambda s: s.strip(),line2.split(",")))
    B = Benefits(vals2[0],vals2[1],vals2[2])

    if vals1[0] == vals2[0]:  #this condition needs to check for all the emp_id's
        E.add_benefits(Benefits(vals2[0],vals2[1],vals2[2]))
print(E)

but i am getting output only for the last emp_id as follows:

>>>print(E)

EMP NO:3,SEX:Male,AGE:28,Benefits:[A10,C2]

This should be the Required output:

EMP NO:1,SEX:Male,AGE:25,Benefits:[A1,B20,A10]
EMP NO:2,SEX:Female,AGE:26,Benefits:[B20]
EMP NO:3,SEX:Male,AGE:28,Benefits:[A10,C2]

could anyone help me with the issue. thanks in advance.

Answer 1

This appears to be the trouble spot:

for line1 in file1:
    vals1 = list(map(lambda s: s.strip(),line1.split(",")))
    E = Employee(vals1[0],vals1[1],vals1[2])

I can see that you're trying to add all 3 lines to your vals1 list, and then print it. The reason only 1 line is showing is because you are redefining both the vals1 and E variables during every iteration . So, instead of adding your data to the list you're actually wiping it out and rewriting it on every pass.

How to fix it:

Create an empty list to store the value of E on every iteration, and print that list at the end of the program, or simply print E at the end of every iteration.