如何遍历对象以删除所有大于100的数字？

Question

I get that I need to use a for in loop, I'm just not sure what I need to put in to remove the properties greater than 100.

Here is the object:

var deleteTheBigNumbers = {
  first: 10,
  second: 20,
  third: 110,
  fourth: 200
}

Answer 1

  for (let key in obj) {
         if (obj[key] >= 100) {
              delete obj[key];
          }
   }

Answer 2

There are numerous ways to handle this. This is one possible way:

 var deleteTheBigNumbers = { first: 10, second: 20, third: 110, fourth: 200 } for (var key in deleteTheBigNumbers) { if (deleteTheBigNumbers[key] >= 100) { delete deleteTheBigNumbers[key]; } } console.log(deleteTheBigNumbers); 

Lodash also has a _.pickBy function which can do this as well:

 var deleteTheBigNumbers = { first: 10, second: 20, third: 110, fourth: 200 } console.log(_.pickBy(deleteTheBigNumbers, (num) => num <= 100)); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script> 

Answer 3

You could write a more generic filtering function.

 var deleteTheBigNumbers = { first: 10, second: 20, third: 110, fourth: 200 }; Object.prototype.oFilter = function (f) { var newobj = {}; var keys = Object.getOwnPropertyNames(this); for (var i = 0; i < keys.length; i += 1) { if (f(this[keys[i]])) { newobj[keys[i]] = this[keys[i]]; } } return newobj; }; var filtered = deleteTheBigNumbers.oFilter(function (v) { return v <= 100; }); console.log(JSON.stringify(filtered));