Calculate total sum of investments in Portfolio?

Question

class Investor:
    def __init__(self,name,investment):
        self.name = name 
        self.investment = investment

    def get_investment(self):
        return self.investment    


class Portfolio:
        def __init__(self,name, investments):
            self.name = name 
            self.investments = []
    
        
        #add investment object to list 
    
        def add_investment(self, investment):
            self.investments.append(investment)
            return True 
    
        def total_investments(self):
            value = 0 
            for investment in self.investments:
                value += investment.add_investment()
            
            return value 
    
    
    
    s1 = Investor('John', 100)
    s2 = Investor('Tim', 150)
    s3 = Investor('Stacy', 50)
    
    
    portfolio = Portfolio('Smt', 300)
    portfolio.add_investment(s1)
    portfolio.add_investment(s2)
    
    print(portfolio.investments[0].investment)

Instead of inputing manually the 300, I want to have a code that will calculate the total size of the investments made by all of the investors in the code:

portfolio = Portfolio('Smt', sum(100 + 150 + 50))

Any help please?

Answer 1

You probably want to create a list. Lists are useful when you have a large number of similar variables that become tiresome to name and assign. I've included a quick-and-dirty introduction to lists in Python, but you can probably find better tutorials on Google.

investors = [              # Here we create a list of Investors;
    Investor("John", 150), # all of these Investors between the
    Investor("Paul", 50),  # [brackets] will end up in the list.
    Investor("Mary", 78)
]

# If we're interested in the 2nd investor in the list, we can access
# it by indexing:
variable = investors[1] # Note indexing starts from 0.

# If we want to add another element to the list,
# we can call the list's append() method
investors.append(Investor("Elizabeth", 453))

# We can access each investor in the list with a for-loop
for investor in investors:
    print(investor.name + " says hi!")

# If we want to process all of the investors in the list, we can use
# Python's list comprehensions:
investments = [ investor.investment for investor in investors ]

If you're interested in getting a better overview of what is possible with lists, I would refer you to W3Schools' Python Tutorial which comes with examples you can run in your browser.