For loop accessing an array of objects with array's

Question

const bankAccounts = [
  {
    id: 1,
    name: "Susan",
    balance: 100.32,
    deposits: [150, 30, 221],
    withdrawals: [110, 70.68, 120],
  },
  { id: 2, name: "Morgan", balance: 1100.0, deposits: [1100] },
  {
    id: 3,
    name: "Joshua",
    balance: 18456.57,
    deposits: [4000, 5000, 6000, 9200, 256.57],
    withdrawals: [1500, 1400, 1500, 1500],
  },
  { id: 4, name: "Candy", balance: 0.0 },
  { id: 5, name: "Phil", balance: 18, deposits: [100, 18], withdrawals: [100] },
];

function getAllWithdrawals(bankAccounts) {
  let newArr = [];
  for (let acc of bankAccounts) {
    if (acc.withdrawals) {
      newArr.push(acc.withdrawals)
    } else if (!acc.withdrawals) {
      newArr.push(0);
    }
  }
  return newArr;
}

I am getting access to the array objects. But how do I get into the objects with the array of withdrawals with varying amounts, add them all and print that in the blank array "newArr"? Do I need another for loop? My overall goal is to iterate through the objects check which ones pass that have withdrawals array. If they do not have a withdrawals array I pass 0. The objects that do have withdrawals I need to iterate through those and add them up and push the total of the withdrawal array into the "newArr".

Can you provide an example of what you would like the output to look like for the accounts given? — NetByMatt
– NetByMatt, Commented Feb 7, 2023 at 19:22
@NetByMatt I added some more text to clarify what I need a little better. — OldsoulPhil
– OldsoulPhil, Commented Feb 7, 2023 at 19:43

Peter Thoeny · Accepted Answer · 2023-02-07 23:01:59Z

2

Here is a functional programming solution that uses map reduce:

const bankAccounts = [ { id: 1, name: "Susan", balance: 100.32, deposits: [150, 30, 221], withdrawals: [110, 70.68, 120], }, { id: 2, name: "Morgan", balance: 1100.0, deposits: [1100] }, { id: 3, name: "Joshua", balance: 18456.57, deposits: [4000, 5000, 6000, 9200, 256.57], withdrawals: [1500, 1400, 1500, 1500], }, { id: 4, name: "Candy", balance: 0.0 }, { id: 5, name: "Phil", balance: 18, deposits: [100, 18], withdrawals: [100] }, ];

function getAllWithdrawals(bankAccounts) {
  return bankAccounts.map(obj => {
    return obj.withdrawals ? obj.withdrawals.reduce((sum, num) => sum + num, 0) : 0;
  });
}

console.log(getAllWithdrawals(bankAccounts));

Output:

Docs:

Intro to map reduce: https://medium.com/poka-techblog/simplify-your-javascript-use-map-reduce-and-filter-bd02c593cc2d
.map(): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map
.reduce(): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reduce

Here is an enhanced version where you pass the deposits or withdrawls key into the function:

const bankAccounts = [ { id: 1, name: "Susan", balance: 100.32, deposits: [150, 30, 221], withdrawals: [110, 70.68, 120], }, { id: 2, name: "Morgan", balance: 1100.0, deposits: [1100] }, { id: 3, name: "Joshua", balance: 18456.57, deposits: [4000, 5000, 6000, 9200, 256.57], withdrawals: [1500, 1400, 1500, 1500], }, { id: 4, name: "Candy", balance: 0.0 }, { id: 5, name: "Phil", balance: 18, deposits: [100, 18], withdrawals: [100] }, ];

function getSums(bankAccounts, key) {
  return bankAccounts.map(obj => {
    return obj[key] ? obj[key].reduce((sum, num) => sum + num, 0) : 0;
  });
}

console.log({
  deposits: getSums(bankAccounts, 'deposits'),
  withdrawals: getSums(bankAccounts, 'withdrawals'),
});

Output:

{
  "deposits": [
    401,
    1100,
    24456.57,
    0,
    118
  ],
  "withdrawals": [
    300.68,
    0,
    5900,
    0,
    100
  ]
}

UPDATE 1: Based on request to use only for loops:

const bankAccounts = [ { id: 1, name: "Susan", balance: 100.32, deposits: [150, 30, 221], withdrawals: [110, 70.68, 120], }, { id: 2, name: "Morgan", balance: 1100.0, deposits: [1100] }, { id: 3, name: "Joshua", balance: 18456.57, deposits: [4000, 5000, 6000, 9200, 256.57], withdrawals: [1500, 1400, 1500, 1500], }, { id: 4, name: "Candy", balance: 0.0 }, { id: 5, name: "Phil", balance: 18, deposits: [100, 18], withdrawals: [100] }, ];

function getAllWithdrawals(bankAccounts) {
  let result = [];
  for (let obj of bankAccounts) {
    let sum = 0;
    if(obj.withdrawals) {
      for (num of obj.withdrawals) {
        sum += num;
      }
    }
    result.push(sum);
  }
  return result;
}

console.log(getAllWithdrawals(bankAccounts));

edited Feb 7, 2023 at 23:01

answered Feb 7, 2023 at 19:27

Peter Thoeny

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5 Comments

OldsoulPhil Over a year ago

can only use for loops

Peter Thoeny Over a year ago

@OldsoulPhil: What is the reason to only use for loops?

OldsoulPhil Over a year ago

trying to teach younger brother some things and I don't know to much about code. I know more than him, but not a lot.

Peter Thoeny Over a year ago

@OldsoulPhil: Gotcha. See UPDATE 1

OldsoulPhil Over a year ago

Thank you. Me and my brother appreciate you. I can help him better with his homework now.

lgalassi · Accepted Answer · 2023-02-07 19:30:06Z

Not sure if I understood your question, but if u have to sum ALL of the withdrawals you should do it in this way:

const bankAccounts = [
  {
    id: 1,
    name: "Susan",
    balance: 100.32,
    deposits: [150, 30, 221],
    withdrawals: [110, 70.68, 120],
  },
  { id: 2, name: "Morgan", balance: 1100.0, deposits: [1100] },
  {
    id: 3,
    name: "Joshua",
    balance: 18456.57,
    deposits: [4000, 5000, 6000, 9200, 256.57],
    withdrawals: [1500, 1400, 1500, 1500],
  },
  { id: 4, name: "Candy", balance: 0.0 },
  { id: 5, name: "Phil", balance: 18, deposits: [100, 18], withdrawals: [100] },
];

function getAllWithdrawals(bankAccounts) {
  let newArr = [];
  for (let acc of bankAccounts) {
    if (!!acc.withdrawals) {
    acc.withdrawals.forEach(withdrawal => newArr.push(withdrawal))
    }
  }
  return newArr.reduce((accumulator, currentValue) => accumulator + currentValue, 0);
}

console.log(getAllWithdrawals(bankAccounts))

Otherwise if you have to sum the withdrawals of the single object you have to use this code:

const bankAccounts = [
  {
    id: 1,
    name: "Susan",
    balance: 100.32,
    deposits: [150, 30, 221],
    withdrawals: [110, 70.68, 120],
  },
  { id: 2, name: "Morgan", balance: 1100.0, deposits: [1100] },
  {
    id: 3,
    name: "Joshua",
    balance: 18456.57,
    deposits: [4000, 5000, 6000, 9200, 256.57],
    withdrawals: [1500, 1400, 1500, 1500],
  },
  { id: 4, name: "Candy", balance: 0.0 },
  { id: 5, name: "Phil", balance: 18, deposits: [100, 18], withdrawals: [100] },
];

function getAllWithdrawals(bankAccounts) {
  let newArr = [];
  for (let acc of bankAccounts) {
    if (!!acc.withdrawals) {
        newArr.push(acc.withdrawals.reduce((accumulator, currentValue) => accumulator + currentValue, 0))
    }
  }
  return newArr;
}

console.log(getAllWithdrawals(bankAccounts))

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