我需要使用循环在数组中找到 18 岁以下的人。 我需要先把它变成一个字符串吗?
我尝试创建一个循环遍历它的函数,但我不确定如何指向 age 属性和返回人员姓名的结果。
var people = [
{ name : 'Matt', age: 19},
{ name : 'George', age: 16},
{ name : 'Ross', age: 12},
{ name : 'Gerard', age: 18},
{ name : 'Leo', age: 15},
{ name : 'Brad', age: 21}
];
控制台中的输出需要如下所示:
George is 16
Ross is 12
Leo is 15
使用过滤器。无需制作字符串
var people = [
{ name : 'Matt', age: 19},
{ name : 'George', age: 16},
{ name : 'Ross', age: 12},
{ name : 'Gerard', age: 18},
{ name : 'Leo', age: 15},
{ name : 'Brad', age: 21}
];
console.log(people.filter(function(e){return e.age<18}))
我认为您可以使用ES6s过滤器方法来存档它。但是你需要为它填充JS。
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
var people = [
{ name : 'Matt', age: 19},
{ name : 'George', age: 16},
{ name : 'Ross', age: 12},
{ name : 'Gerard', age: 18},
{ name : 'Leo', age: 15},
{ name : 'Brad', age: 21}
];
function isJung(p){
return p.age <18 ;
}
var youngPeople = people.filter(isJung);
而 polyfil 也由 Mozilla 提供:
if (!Array.prototype.filter){
Array.prototype.filter = function(func, thisArg) {
'use strict';
if ( ! ((typeof func === 'Function' || typeof func === 'function') && this) )
throw new TypeError();
var len = this.length >>> 0,
res = new Array(len), // preallocate array
t = this, c = 0, i = -1;
var kValue;
if (thisArg === undefined){
while (++i !== len){
// checks to see if the key was set
if (i in this){
kValue = t[i]; // in case t is changed in callback
if (func(t[i], i, t)){
res[c++] = kValue;
}
}
}
}
else{
while (++i !== len){
// checks to see if the key was set
if (i in this){
kValue = t[i];
if (func.call(thisArg, t[i], i, t)){
res[c++] = kValue;
}
}
}
}
res.length = c; // shrink down array to proper size
return res;
};
}
起初filter
然后map
var people = [
{ name : 'Matt', age: 19},
{ name : 'George', age: 16},
{ name : 'Ross', age: 12},
{ name : 'Gerard', age: 18},
{ name : 'Leo', age: 15},
{ name : 'Brad', age: 21}
];
console.log(people.filter(function(e){return e.age<=18}).map(x => x.name+" is " +x.age));
使用过滤器来保留好的,并显示foreach。
const people = [
{ name : 'Matt', age: 19},
{ name : 'George', age: 16},
{ name : 'Ross', age: 12},
{ name : 'Gerard', age: 18},
{ name : 'Leo', age: 15},
{ name : 'Brad', age: 21}
];
people.filter(v => v.age < 18).forEach((v)=>{console.log(`${v.name} is ${v.age}`)})
使用 ES6 javascript:
people.forEach((single) => {
if(single.age < 18)
console.log(`${single.name} is ${single.age}`);
});