如何在javascript中成对加入数组元素

Question

I have a array of numbers [1,2,3,4,5,6,7,8,9,10] and I want to make it into a string like this: '1,2 3,4 5,6 7,8 9,10'. Is there some fast and simple vay to do this in javascript or do i have to use the loop?

for(let i = 0; i < array.length; i++){
     if(i%2 == 0){
        res += array[i] + ',';
     } else {
        res += array[i] + ' ';
     }
}

Answer 1

You could get pairs with comma and then join the array with spaces for the string, but you need still a loop

 var array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], temp = [], i = 0, string; while (i < array.length) { temp.push(array.slice(i, i += 2).join()); } string = temp.join(' '); console.log(string); 

Answer 2

You can use reduce to get the result you desire:

[1,2,3,4,5,6,7,8,9,10]
    .reduce((acc, val, idx) => 
        idx % 2 === 0 
            ? (acc ? `${acc} ${val}` : `${val}`) 
            : `${acc},${val}`, '') 
// "1,2 3,4 5,6 7,8 9,10"

By taking advantage of the third parameter of the reduce function we know the index of the element we are currently iterating over, therefore also making this function work for arrays that aren't numbers 1 through 10.

Answer 3

You could chunk the array, and join the elements with commas and spaces:

 var arr = [1,2,3,4,5,6,7,8,9,10,11] chunkArr = arr.reduce((acc, item, index) => { const i = Math.floor(index/2) if(!acc[i]) { acc[i] = [] } acc[i].push(item) return acc }, []) arr = chunkArr.map(arr => arr.join(',')).join(' ') console.log(arr) 

Note, this code works with an odd amount of numbers too.