js小题狂练(5)--拆分数字

expandedForm(12); // Should return '10 + 2'

expandedForm(42); // Should return '40 + 2'

expandedForm(70304); // Should return '70000 + 300 + 4'

人类的解法：

function expandedForm(num) {

res={};

ans=[];

var weight=1;

while(num)

{

res[weight]=num%10;

weight*=10;

num=parseInt(num/10);

}

for(var i in res)

{

if(res[i])

ans.unshift(i*res[i])

}

ans=ans.join(' + ');

//console.log(ans);

return ans;

}

es 6 箭头极简风格

const expandedForm = n => n.toString()

.split("")

.map((num,index,arr) => num+'0'.repeat(arr.length-index-1))

.filter((num) => Number(num)!=0)

.join(' + ');

console.log(expandedForm(70304));