在javascript中交错多个数组 [英] interleave mutliple arrays in javascript
问题描述
我们有一个数组数组,我们想将其交织到一个数组中:即:
We have an Array of arrays, which we want to interleave into a single array: i.e:
masterArray = [[1,2,3],['c','d','e']] =>[1,'c',2,'d',3,'e'],
masterArray = [[1, 2, 3], ['c', 'd', 'e']] => [1, 'c', 2, 'd', 3, 'e'],
如果数组的长度不相等,则将其填充到最长的innerArray长度.
if arrays are not of equal length, pad it to the longest innerArray's length.
即[1、2、3],[4、5])=>[1、4、2、5、3,空]
i.e [1, 2, 3], [4, 5]) => [1, 4, 2, 5, 3, null]
对于2个数组,我已经满足了此条件,但是如果大小写不止于此.我努力制定一项应对超过2个问题的策略.
I've satisfied this condition with the case of 2 arrays, however if the case is more than that. I struggle to form a strategy on dealing with more than 2.
[1、2、3],[4、5、6],[7、8、9] =>[1、4、7、2、5、8、3、6、9]
[1, 2, 3], [4, 5, 6], [7, 8, 9] => [1, 4, 7, 2, 5, 8, 3, 6, 9]
function interleave(...masterArray) {
let rtnArray = [];
let longestArrayPosition = getLongestArray(masterArray);
let longestInnerArrayLength = masterArray[longestArrayPosition].length;
padAllArraysToSameLength(masterArray, longestInnerArrayLength); //pad uneven length arrays
masterArray[0].forEach((firstArrayNum, index) => {
const secondArrayNum = masterArray[1][index];
rtnArray.push(firstArrayNum);
rtnArray.push(secondArrayNum);
});
return rtnArray;
}
function getLongestArray(masterArray) {
return masterArray
.map(a=>a.length)
.indexOf(Math.max(...masterArray.map(a=>a.length)));
}
function padAllArraysToSameLength(masterArray, maxLength) {
return masterArray.forEach(arr => {
if (arr != maxLength) {
while(arr.length != maxLength) {
arr.push(null);
}
}
})
}
推荐答案
您可以对带有两个嵌套的forEach语句的任意数量的数组执行此操作:
You can do this for any number of arrays with two nested forEach statements:
let arr1 = [[1,2,3],[4,5]]
let arr2 = [[1,2,3], [4,5,6], [7,8,9]]
let arr3 = [[1,2,3,4], [4,5,6], [7,8,9], [10,11,12]]
function interLeaveArrays(mainArr){
let maxLen = Math.max(...mainArr.map(arr => arr.length))
mainArr.forEach(arr => {
let lenDiff = maxLen - arr.length
for(let i=lenDiff; i>0; i--){
arr.push(null)
}
})
let newArr = []
mainArr.forEach((arr, idx1) => {
arr.forEach((el, idx2) => {
newArr[idx2 * mainArr.length + idx1] = el
})
})
return newArr
}
console.log(interLeaveArrays(arr1))
console.log(interLeaveArrays(arr2))
console.log(interLeaveArrays(arr3))
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