gaspersic/freeCodeCamp
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Update index.md (#22622)

Browse Source 
more easy to understand and short than all other solutions
This commit is contained in:
VitBu
2018-11-25 19:53:00 +02:00
committed by Christopher McCormack
parent 6b961cd407
commit 9fb1d9f49c
1 changed files with 19 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
guide/english/certifications/javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/sum-all-primes/index.md
View File

@ -132,6 +132,25 @@ This problem is hard if you have to create your own code to check for primes, so
* <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Functions#Recursion' target='_blank' rel='nofollow'>Functions - Recursion</a>
## ![:sunflower:](https://forum.freecodecamp.com/images/emoji/emoji_one/sunflower.png?v=3 ":sunflower:") Intermediate Code Solution 2:
function sumPrimes(num) {
let nums = Array.from({length: num + 1}).map((_, i) => i).slice(2);
for (let n in nums) {
nums = nums.filter(val => val == nums[n] || val % nums[n] != 0);
}
return nums.reduce((prevSum, cur) => prevSum + cur);
}
// test here
sumPrimes(13);
![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") <a href='https://repl.it/repls/FrigidFantasticFossil' target='_blank' rel='nofollow'>Run Code</a>
### Code Explanation:
* Use `Array.from()` to generate a sequence of numbers up to and including `num`. Combine with `.slice()` to slice off first two indices `[0, 1]` since all prime numbers must be greater than 1.
* If a number is not prime, it is divided by number > 1 other smaller than himself.
## ![:rotating_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/rotating_light.png?v=3 ":rotating_light:") Advanced Code Solution:
function sumPrimes(num) {