Angular 4 - Sum of Array

Question

new to ng4/typescript and having some difficulty. How do I sum the items in an array?

Added screenshot of what it looks like in action for example

        for (let card of this.cards) {
              for (let val of card.cards){
                if(val.value == "JACK"){
                  val.value = 10;
                }
                if (val.value == "QUEEN"){
                  val.value = 10;
                }
                if (val.value == "KING"){
                  val.value = 10;
                }
                if (val.value == "ACE"){
                  val.value = 10;
                }

                this.hand = Number(val.value) + Number(val.value); (I'm sure this is wrong)

             }
          }

Start by a simpler task. Try summing the elements of the following array: [1, 2, 3, 4]. — JB Nizet, Nov 04 '17 at 17:09
Possible duplicate of [How to find the sum of an array of numbers](https://stackoverflow.com/questions/1230233/how-to-find-the-sum-of-an-array-of-numbers) — edkeveked, Nov 04 '17 at 17:15

score 10 · Accepted Answer · answered Nov 04 '17 at 17:31

10

Use Array#Reduce:

// Array of numbers
var array = [1,2,3,4,5];
var sum = array.reduce((acc, cur) => acc + cur, 0);
console.log(sum)

// Array of strings
var toNumber = ['1','2','3','4','5'];
var sumNumber = toNumber.reduce((acc, cur) => acc + Number(cur), 0)
console.log(sumNumber);

answered Nov 04 '17 at 17:31

Marko Savic

2,159
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That's the thing, I tried this before I posted the question. toNumber doesn't work, it's just Number() in angular 4. Additionally, Number can't be called with reduce. That's the dilemma – Chris Simmons Nov 04 '17 at 17:41
@ChrisSimmons use than `parseFloat` or `parseInt` insted Number. – Marko Savic Nov 04 '17 at 17:45
@ChrisSimmons If this solution works for you, mark answer as correct. Thank you. – Marko Savic Jun 10 '18 at 20:08

score 1 · Answer 2 · answered Nov 03 '19 at 21:40

1

let sum = array.reduce(function (acc, cur) { return acc + cur; });

answered Nov 03 '19 at 21:40

Danilo

631
1
9
24

Whilst this answer may be correct, some explanation of why and how would go a long way. – Smokey Dawson Nov 04 '19 at 01:56
the array.reduce((acc, cur) => acc + cur, 0); not work on AnularJS old versions, this that i have wrote works for all versions – Danilo Nov 04 '19 at 09:17

Angular 4 - Sum of Array

2 Answers2