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[js] 第119天 写一个方法把多维数组降维#1059
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@haizhilin2013

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@haizhilin2013
haizhilin2013
opened on Aug 12, 2019
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第119天 写一个方法把多维数组降维

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haizhilin2013
added
jsJavaScript
on Aug 12, 2019
fengyun2

fengyun2 commented on Aug 13, 2019

@fengyun2
fengyun2
on Aug 13, 2019
const arr = [1, 2, [3, 4, [5, 6]]]
arr.flat(Infinity)
// [1, 2, 3, 4, 5, 6]
NicholasBaiYa

NicholasBaiYa commented on Aug 13, 2019

@NicholasBaiYa
NicholasBaiYa
on Aug 13, 2019
function flattenDeep(arr) {
   return arr.reduce((acc, val) => Array.isArray(val) ? acc.concat(flattenDeep(val)) : acc.concat(val), []);
}

抄MDN上的，会把空项过滤。

nowherebutup

nowherebutup commented on Aug 13, 2019

@nowherebutup
nowherebutup
on Aug 13, 2019
  function handlerArr(arr, _rst) {
    const rst = _rst || [];
    arr.forEach(ele => {
      typeof ele === 'object' ? handlerArr(ele, rst) : rst.push(ele);
    });
    return rst;
  }
LinStan

LinStan commented on Aug 13, 2019

@LinStan
LinStan
on Aug 13, 2019
let arr = [1, 2, {}, 3, [4, {}, 5], [6, 7, [8, null, 9]]];
//递归
function flat (arr) {
  let ret = []
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] instanceof (Array)) {
      ret = ret.concat(flat(arr[i]))
    }
    else {
      ret.push(arr[i])
    }
  }
  return ret
}
console.log(flat(arr))
//ES10新增的内置方法
arr.flat(Infinity)
HuoXiaoYe

HuoXiaoYe commented on Aug 13, 2019

@HuoXiaoYe
HuoXiaoYe
on Aug 13, 2019
		function flatArr(arr){
			var result = [];
			arr.forEach((item)=>{
				if(Array.isArray(item)){
					let subResult = flatArr(item);
					result = result.concat(subResult);
				}else{
					result[result.length] = item;
				}
			})
			return result;
		}
		console.log(flatArr([1, 2, [3, 4, [5, 6]]])) // [1, 2, 3, 4, 5, 6]
ghost

ghost commented on Aug 13, 2019

@ghost
ghost
on Aug 13, 2019
function flatten(arr, depth = 1) {
    if (!depth || !Array.isArray(arr)) return arr
    return arr.reduce((prev, mem) => 
        prev.concat(flatten(mem, depth - 1)), [])
}

怎么感觉和搬mdn的那位这么像...但是这个支持指定深度。

LJH520

LJH520 commented on Aug 13, 2019

@LJH520
LJH520
on Aug 13, 2019

https://blog.csdn.net/LJH111101/article/details/99413887

Konata9

Konata9 commented on Aug 13, 2019

@Konata9
Konata9
on Aug 13, 2019 · edited by Konata9
const flatArr = (arr, deep = false) =>
  arr.reduce((prev, cur) => {
    if (deep && Array.isArray(cur)) {
      return prev.concat(flatArr(cur, deep));
    } else {
      return prev.concat(cur);
    }
  }, []);

const arr = [1, [2, [3, [4, [5], 6], 7], 8], 9];
const arr2 = [{}, [{}, {}, {}, [2, 3, 4, [5, 6, 7, [{}, {}]]]]];
console.log(flatArr(arr, true));
Jingce-lu

Jingce-lu commented on Nov 7, 2019

@Jingce-lu
Jingce-lu
on Nov 7, 2019
const flatArr = (arr) => Array.isArray(arr)
  ? arr.reduce( (a, b) => [...a, ...flatArr(b)] , [])
  : [arr]

flatArr([1, [[2], [3, [4]], 5]])
zhaofeipeter

zhaofeipeter commented on Jul 30, 2020

@zhaofeipeter
zhaofeipeter
on Jul 30, 2020 · edited by zhaofeipeter

const flatArray = arr => arr.flat(Infinity);

xiaoqiangz

xiaoqiangz commented on Jul 7, 2022

@xiaoqiangz
xiaoqiangz
on Jul 7, 2022

const arr = [2,3,[4,5,6],[7,9,0],10,[344,666,[888,999]]]
function flat(data) {
return data.reduce((prev,cur) => {
if (Array.isArray(cur)) {
return prev.concat(flat(cur))
} else {
return prev.concat(cur)
}
},[])
}
let arr1 = flat(arr)
console.log(arr1)

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          [js] 第119天 写一个方法把多维数组降维 · Issue #1059 · haizlin/fe-interview