給定以下結構：
const data = {
"show": "Family Guy",
"characters": [
[{name: 'Peter', age: 40, city: 'Quahog'}],
[{name: 'Louis', age: 30}],
[{name: 'Chris', age: 16}],
[{name: 'Stewie', age: 1}]
]
}
我們如何向每個字符添加鍵/值對，city: 'Quahog'以便輸出如下所示：
const item = {
"show": "Family Guy",
"characters": [
[{name: 'Peter', age: 40, city: 'Quahog'}],
[{name: 'Louis', age: 30, city: 'Quahog'}], // city added
[{name: 'Chris', age: 16, city: 'Quahog'}], // city added
[{name: 'Stewie', age: 1, city: 'Quahog'}] // city added
]
}
我們嘗試使用：
let city = data.characters.[0][0].city;
costs = _.map(items, (itemArray) => {
items = _.map(itemArray, (item) => {
if(!item.city) {
item.city = city;
}
});
但它沒有按預期作業，我們無法獲得所需的輸出。知道如何做到這一點嗎？
uj5u.com熱心網友回復：
不確定擁有這些單項陣列的原因，但此解決方案可以完成作業（我建議您查看創建此資料格式的程序，這有點奇怪）
const data = {
"show": "Family Guy",
"characters": [
[{name: 'Peter', age: 40, city: 'Quahog'}],
[{name: 'Louis', age: 30}],
[{name: 'Chris', age: 16}],
[{name: 'Stewie', age: 1}]
]
}
const city = data.characters.find(characters => characters.find(character => character.city))[0].city
const dataWithCities = {
...data,
characters: data.characters.map(characters => characters.map(character => character.city ? character : {...character, city}))
}
console.log(dataWithCities)uj5u.com熱心網友回復：
這是另一種方法.reduce()：
const data = {
"show": "Family Guy",
"characters": [
[{name: 'Peter', age: 40, city: 'Quahog'}],
[{name: 'Louis', age: 30}],
[{name: 'Chris', age: 16}],
[{name: 'Stewie', age: 1}]
]
};
data.characters.reduce((a,c)=>
(c[0].city=a[0].city,a));
console.log(data);當.reduce()不使用第二個引數時，它將選擇第一個陣列元素作為初始值，然后將其用作模板以將.city屬性復制到所有其他元素。方法的實際回傳值.reduce()被丟棄，但輸入陣列本身 ( data) 在此程序中被修改，然后顯示在console.log()運算式中。
uj5u.com熱心網友回復：
試試這個
let city = data.characters.[0][0].city;
let newdata = [];
data.characters.map(items, (itemArray) => {
items = _.map(itemArray, (item) => {
if(item.city === undefined) {
newdata.push({...item , city});
} else {
newdata.push({...item});
}
})
costs = {...newdata}
uj5u.com熱心網友回復：
你可以在沒有 lodash 的情況下做到這一點
const data = {
"show": "Family Guy",
"characters": [
[{name: 'Peter', age: 40, city: 'Quahog'}],
[{name: 'Louis', age: 30}],
[{name: 'Chris', age: 16}],
[{name: 'Stewie', age: 1}]
]
}
const chars = data.characters.map((x)=>{
return {...x[0] , city : x[0].city ? x[0].city : city}
})
const items = {...data , characters : chars};
uj5u.com熱心網友回復：
const { city } = data.characters.find(([item]) => !!item.city?.length)[0];
const newData = {
...data,
characters: data.characters.map(([char]) => [{ ...char, city }])
};
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標籤：javascript 数组 罗达什