Question

function(people){

}
people([{name: 'John', age: 22},{name: 'paul', age: 23},{name: 'mathew', age: 24},])

如何返回由22岁以上的人组成的数组的长度，应该为2。

Answer 1

您可以使用array reduce进行计数：

function people(array){
  return array.reduce((total, current)=>{
    if(current.age>22)
      total = total +1;
    return total;
  },0);
}
console.log(people([{name: 'John', age: 22},{name: 'paul', age: 23},{name: 'mathew', age: 24},]));

Answer 2

下面是针对您的问题的功能编程方法：

const persons = [
  {name: 'John', age: 22},
  {name: 'paul', age: 23},
  {name: 'mathew', age: 24}
  ]
  
const over22 = persons.filter(person => person.age > 22)

console.log('there are', over22.length, 'people aged over 22')

希望这会有所帮助。干杯，

Answer 3

请尝试以下操作：

function find_length(checkField, valueField, myArray) {
  for (var i = 0; i < myArray.length; i++) {
      if (myArray[i][checkField] == valueField) {
         return Object.keys(myArray[i]).length;
      }
  }
}

var myList = [{name: 'John', age: 22}, {name: 'paul', age: 23}, {name: 'mathew', age: 24},];
var ageObjLength = find_length('age', '22', myList );
alert("Length is " + ageObjLength);

返回带有条件的数组的长度

3 个答案: