CODEWITHSUNDEEP
javascriptarrays
Yu Jia
Yu Jia

Reputation: 353

Javascript what is the best way to find a first item, that meet condition in an array of arrays

If I have an array of arrays looks like following,

const ar = [
   [2,6,7,9],
   [3,2,4,6],
   [7,8,9,10]
];

what will be a smart way to return the first item, that contains a number 3. want to get an array [3,2,4,6]. Thanks

Upvotes: 0

Views: 109

Answers (2)

akaphenom
akaphenom

Reputation: 6888

something like

ar.find(innerAr -> innerAr.includes(3))

should work. I would encapsulate the solution along these lines:

 const findInnerArrayWith = val => arr => 
        arr.find(innerAr -> innerAr.includes(val))

in use this would be:

 const findInnerArrayWith3 = findInnerArrayWith(3)
 const inner = findInnerArrayWith(ar)

or if you want to run multiple queries against the array (holding the array constant and varying the object to find) I might flip the parameters

 const findIn = arr => val => 
        arr.find(innerAr -> innerAr.includes(val))

 const findInAr = findIn(ar)
 const inner = findInAr(3)

maybe thats a bit beyond the scope of the question - but the order of the parameters opens up some interesting approaches to structuring your code.

references

Upvotes: 1

HW Siew
HW Siew

Reputation: 1003

This is an example how you can do it with array find and indexOf. Simply put, array.find looks for the first element matches an condition. And the condition is where the array.indexOf comes in to check the membership of target in an array.

const ar = [
   [2,6,7,9],
   [3,2,4,6],
   [7,8,9,10]
];
const target = 3; // the target number you are looking

let result = ar.find( a => a.indexOf(3) !== -1);

Upvotes: 1

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