如何在JavaScript中匹配二维数组中的对？

Question

I have an array with pairs of numbers and need to find matching pairs within the array

numberStore = [ [0,0],[1,1],[1,2],[1,3],[1,4],[1,5]... ]

I want to be able to find 1,4 . Is there a way to find this array without relying on numberStore[4] ?

Answer 1

Since you need to perform this search frequently, I would build a hashed set to avoid mapping and searching over and over. For example

 const numberStore = [ [0,0],[1,1],[1,2],[1,3],[1,4],[1,5] ] const hashedSet = new Set(numberStore.map(pair => pair.toString())) // looks like ["0,0", "1,1", "1,2", "1,3", etc] console.log([...hashedSet]) const search = (find) => { return hashedSet.has(find.toString()) } console.info('Find [1,4]', search([1,4])) console.info('Find [4,1]', search([4,1])) 

I've used Array.prototype.toString() as the hashing function but you could substitute anything there that creates a unique and comparable entity for each pair.

Answer 2

Use Array.prototype.find() :

 var numberStore = [ [0, 0], [1, 1], [1, 2], [1, 3], [1, 4], [1, 5] ]; var oneFour = numberStore.find(function([a, b]) { return a == 1 && b == 4; }); console.log(oneFour); 

Or if you prefer ES6 arrow syntax :

 var numberStore = [ [0, 0], [1, 1], [1, 2], [1, 3], [1, 4], [1, 5] ]; var oneFour = numberStore.find(([a, b]) => a == 1 && b == 4); console.log(oneFour); 

Answer 3

Another alternative is using the method some() to test elements for a condition.

 var numberStore = [ [0,0], [1,1], [1,2], [1,3], [1,4], [1,5] ]; var exists = numberStore.some(([a, b]) => a === 1 && b === 4); console.log(exists ? "Pair [1,4] exists" : "Pair [1,4] don't exists");