求城市平均年龄

骑猪看日落 2022-12-17 07:24 176阅读 0赞

// 求城市的平均年龄
    const people = [{ 
            name: "som",
            age: 35,
            city: "beijing ",
        },
        { 
            name: "tom",
            age: 25,
            city: "chengdu ",
        },
        { 
            name: "frank",
            age: 45,
            city: "shanghai ",
        },
        { 
            name: "mary",
            age: 35,
            city: "chengdu ",
        },
        { 
            name: "frank",
            age: 45,
            city: "shanghai ",
        },
    ];

### 方法1 ###

//方法1
    function FC(people) { 
        console.log(people, "people");
        let result = { };
        let city = [];
        people.map((item) => { 
            city.push(item.city);
        });
        city = city.filter((item, index, array) => { 
            return array.indexOf(item) === index;
        });
        for (let j = 0; j < city.length; j++) { 
            let len = 0;
            result[city[j]] = 0;
            people.map((item) => { 
                if (item.city == city[j]) { 
                    result[city[j]] += item.age;
                    len++;
                }
            });
            if (len > 1) { 
                result[city[j]] = result[city[j]] / len;
            }
        }
        console.log(city, "city");
        return result;
    }
    console.log(FC(people), "result");
    //{“chengdu ”: 30,“beijing ”:35,“shanghai ”:45}

### 方法2 ###

方法2
    function Fc(people) { 
        let result = { };
        let len = { };
        people.map((item, index) => { 
            let keys = Object.keys(item);
            console.log(keys);
            let values = Object.values(item);
            console.log(values);
            if (!result[values[2]]) { 
                result[values[2]] = 0;
                len[values[2]] = 0;
                console.log(result);
                console.log(len[values[2]]);
            }
            result[values[2]] += values[1];
            len[values[2]]++;
        });
        for (let i in result) { 
            result[i] = result[i] / len[i];
        }
        return result;
    }
    console.log(Fc(people));

### 方法3 ###