Purpose of project: allow an employee to calculate/project future 401k yearly balances based on several future promotions. With promotions come pay raises.
Current challenge to overcome: create a function that finds the sum of each year's roth and traditional 401k balances. If the employee's roth 401k balance array were [$1000, $2000, $3000] and his traditional 401k balance array were [$100, $200, $300] (each element representing a year), the resulting combined balances array would be [$1100, $2200, $3300].
The entire code (version 0.2.0) is found on GitHub here.
Here are the sections that relate to the roth and traditional balance arrays which are found following the calc401k() function:
func balanceOfRoth() -> [Decimal] {
//chunk the employmentHistory into years (i.e., 12-month groups
let years = employmentHistory.chunked(into: 12)
//start with an empty array of how much the employee
// puts into their Roth account each year
var averageRothContribution: [Decimal] = []
for (index, months) in years.enumerated() {
//for one year, how much was contributed by the employee
// to their Roth account?
let yearToRoth: Decimal = months.reduce(0) { runningTotal, dept in
//what is the payRate for this month given a department
// and a number of years worked?
let payRate = dept.payRate(forYearsWorked: index + 1)
//calculate how much was put into the Roth account
// this month
let monthlyToRoth = Calculations.computeMonthly401kDeposits(
hours: monthlyHoursWorked,
atPayRate: payRate,
percentTo401k: percentToRoth
)
//add the monthly Roth amount to the amounts for the
// rest of the amounts in this year
return runningTotal + monthlyToRoth
}
//add the average of this year's amounts to the array of other year average amounts
averageRothContribution.append(yearToRoth / Decimal(months.count))
}
//averageRothContribution now contains the average amount
// in each year that the employee contributed
//start with an empty array of the balance in the
// employee's Roth account on a yearly basis
var rothBalances: [Decimal] = []
for idx in averageRothContribution.indices {
//our principal will either be existingBalance (for the first item)
// or the previous item (for items 2...n)
let principal = idx == 0
? existing401kbalance
: rothBalances[idx - 1]
//calculate the yearly balance
let balance401k = calc401k(principal: principal,
deposits: averageRothContribution[idx],
rateOfReturn: Decimal(marketReturnRate)
)
//and add it to our list of balances
rothBalances.append(balance401k)
}
//give it back to the caller
return rothBalances
}
func balanceOfTrad() -> [Decimal] {
//chunk the employmentHistory into years (i.e., 12-month groups
let years = employmentHistory.chunked(into: 12)
//start with an empty array of how much the employee
// puts into their Trad account each year
var averageTradContribution: [Decimal] = []
for (index, months) in years.enumerated() {
//for one year, how much was contributed by the employee
// to their Trad account?
let yearToTrad: Decimal = months.reduce(0) { runningTotal, dept in
//what is the payRate for this month given a department
// and a number of years worked?
let payRate = dept.payRate(forYearsWorked: index + 1)
//calculate how much was put into the Trad account
// this month
let monthlyToTrad = Calculations.computeMonthly401kDeposits(
hours: monthlyHoursWorked,
atPayRate: payRate,
percentTo401k: percentToTrad
)
//add the monthly Trad amount to the amounts for the
// rest of the amounts in this year
return runningTotal + monthlyToTrad
}
//add the average of this year's amounts to the array of other year average amounts
averageTradContribution.append(yearToTrad / Decimal(months.count))
}
//averageRothContribution now contains the average amount
// in each year that the employee contributed
//start with an empty array of the balance in the
// employee's Roth account on a yearly basis
var tradBalances: [Decimal] = []
for idx in averageTradContribution.indices {
//our principal will either be existingBalance (for the first item)
// or the previous item (for items 2...n)
let principal = idx == 0
? existing401kbalance
: tradBalances[idx - 1]
//calculate the yearly balance
let balance401k = calc401k(principal: principal,
deposits: averageTradContribution[idx],
rateOfReturn: Decimal(marketReturnRate)
)
//and add it to our list of balances
tradBalances.append(balance401k)
}
//give it back to the caller
return tradBalances
}
Currently the balanceOfRoth() and balanceOfTrad() are separate functions. Each contains an array (rothBalances: [Decimal] & tradBalances: [Decimal]) I would like to create a function that finds of the sum of the elements between the arrays. First element of rothBalances + first element of tradBalances to find total 401k balance for that given year. And so on for each successive year/element.
Here is a clunky way of potentially finding a solution:
func balanceOfCombined() -> [Decimal] {
//chunk the employmentHistory into years (i.e., 12-month groups
let years = employmentHistory.chunked(into: 12)
//start with an empty array of how much the employee
// puts into their Trad account each year
var averageTradContribution: [Decimal] = []
for (index, months) in years.enumerated() {
//for one year, how much was contributed by the employee
// to their Trad account?
let yearToTrad: Decimal = months.reduce(0) { runningTotal, dept in
//what is the payRate for this month given a department
// and a number of years worked?
let payRate = dept.payRate(forYearsWorked: index + 1)
//calculate how much was put into the Trad account
// this month
let monthlyToTrad = Calculations.computeMonthly401kDeposits(
hours: monthlyHoursWorked,
atPayRate: payRate,
percentTo401k: percentToTrad
)
//add the monthly Trad amount to the amounts for the
// rest of the amounts in this year
return runningTotal + monthlyToTrad
}
//add the average of this year's amounts to the array of other year average amounts
averageTradContribution.append(yearToTrad / Decimal(months.count))
}
//averageRothContribution now contains the average amount
// in each year that the employee contributed
//start with an empty array of the balance in the
// employee's Roth account on a yearly basis
var tradBalances: [Decimal] = []
for idx in averageTradContribution.indices {
//our principal will either be existingBalance (for the first item)
// or the previous item (for items 2...n)
let principal = idx == 0
? existing401kbalance
: tradBalances[idx - 1]
//calculate the yearly balance
let balance401k = calc401k(principal: principal,
deposits: averageTradContribution[idx],
rateOfReturn: Decimal(marketReturnRate)
)
//and add it to our list of balances
tradBalances.append(balance401k)
}
//give it back to the caller
return tradBalances
var averageRothContribution: [Decimal] = []
for (index, months) in years.enumerated() {
//for one year, how much was contributed by the employee
// to their Roth account?
let yearToRoth: Decimal = months.reduce(0) { runningTotal, dept in
//what is the payRate for this month given a department
// and a number of years worked?
let payRate = dept.payRate(forYearsWorked: index + 1)
//calculate how much was put into the Roth account
// this month
let monthlyToRoth = Calculations.computeMonthly401kDeposits(
hours: monthlyHoursWorked,
atPayRate: payRate,
percentTo401k: percentToRoth
)
//add the monthly Roth amount to the amounts for the
// rest of the amounts in this year
return runningTotal + monthlyToRoth
}
//add the average of this year's amounts to the array of other year average amounts
averageRothContribution.append(yearToRoth / Decimal(months.count))
}
//averageRothContribution now contains the average amount
// in each year that the employee contributed
//start with an empty array of the balance in the
// employee's Roth account on a yearly basis
var rothBalances: [Decimal] = []
for idx in averageRothContribution.indices {
//our principal will either be existingBalance (for the first item)
// or the previous item (for items 2...n)
let principal = idx == 0
? existing401kbalance
: rothBalances[idx - 1]
//calculate the yearly balance
let balance401k = calc401k(principal: principal,
deposits: averageRothContribution[idx],
rateOfReturn: Decimal(marketReturnRate)
)
//and add it to our list of balances
rothBalances.append(balance401k)
}
//give it back to the caller
return rothBalances
var combinedBalances: [Decimal] = []
// somehow append the sum of each element of both roth and trad arrays into this combinedBalances array
}
What I did above was simply combine the trad and roth balance functions so that the tradBalances and rothBalances would be accessible within one function. But I'm not sure how to loop through those two arrays to find the sum of individual corresponding elements.
The current print is:
Roth 401k Balance Year 3: 3115.20396231420428012956723300993944886
Trad 401k Balance Year 3: 4321.4984992379485032529639916373900652
Roth 401k Balance Year 4: 5853.9955987608963897745354300607654945
Trad 401k Balance Year 4: 8634.1583811920981350630169897649985946
(and so on...)
The combinedBalances function should be a simple sum of roth and trad. The combined balance for year three should be 7,436.69 (3315.20 + 4321.49). And year four should be 14,488.14 (5853.99 + 8634.15).
