我想合并两个包含有关电影信息的JSON文件。这些文件有一些共同的项目。我想写第三个文件，其中包含所有电影而不重复它们。
这是我到目前为止所拥有的：
const fs = require('fs');
const path = require('path');
const readMovies1 = () => {
return new Promise((resolve, reject) => {
fs.readFile(path.join(__dirname,'../models/movies.json'), 'utf8', (err, data1) => {
if(err) reject(err);
let data = JSON.parse(data1);
resolve(data);
});
});
};
const readMovies2 = (data1) => {
return new Promise((resolve, reject) =>{
fs.readFile(path.join(__dirname,'../models/movies2.json'), 'utf8', (err, data) => {
if(err) reject(err);
data = JSON.parse(data);
resolve([data1,data]);
});
});
};
const merging = (data1, data2) => {
var args = arguments;
var hash = {};
var arr = [];
for (var i = 0; i < args.length; i++) {
for (var j = 0; j < args[i].length; j++) {
if (hash[args[i][j]] !== true) {
arr[arr.length] = args[i][j];
hash[args[i][j]] = true;
}
}
}
return arr;
};
readMovies1()
.then(readMovies2)
.catch((err) => console.error(err))
.then((data) => console.log(merging(data[0],data[1])))
.catch((err) => console.error(err));
但是控制台输出给了我这个：
[ undefined,
'/',
'U',
's',
'e',
'r',
'g',
'o',
'n',
'z',
'P',
'j',
'c',
't',
'J',
'S',
'a',
'd',
'm',
'-',
'v',
'i',
'l',
'b',
'.' ]
我在堆栈溢出的问题中找到了合并函数，但它正在合并一个数组，我正在合并对象数组。我不知道这是否与我的问题有关。
这是我的一个源文件（另一个遵循相同的模式，但有其他一些电影）：
[{
"title": "Spider-Man: Homecoming",
"usersScore": "92%",
"criticsScore": "89%"
}, {
"title": "Girls Trip",
"usersScore": "89%",
"criticsScore": "83%"
}, {
"title": "Captain Underpants: The First Epic Movie (Captain Underpants)",
"usersScore": "87%",
"criticsScore": "62%"
}, {
"title": "Guardians of the Galaxy Vol. 2",
"usersScore": "82%",
"criticsScore": "88%"
}, {
"title": "Wonder Woman",
"usersScore": "92%",
"criticsScore": "89%"
}, {
"title": "First They Killed My Father",
"usersScore": "88%",
"criticsScore": "83%"
}, {
"title": "Baby Driver",
"usersScore": "93%",
"criticsScore": "87%"
}, {
"title": "Demon",
"usersScore": "91%",
"criticsScore": "56%"
}, {
"title": "The Music of Strangers: Yo-Yo Ma and the Silk Road Ensemble",
"usersScore": "84%",
"criticsScore": "85%"
}, {
"title": "Colossal",
"usersScore": "80%",
"criticsScore": "59%"
}, {
"title": "Certain Women",
"usersScore": "92%",
"criticsScore": "51%"
}, {
"title": "Godzilla Resurgence (Shin Godzilla)",
"usersScore": "84%",
"criticsScore": "73%"
}, {
"title": "My Cousin Rachel",
"usersScore": "76%",
"criticsScore": "47%"
}, {
"title": "The Meyerowitz Stories (New and Selected)",
"usersScore": "93%",
"criticsScore": "84%"
}, {
"title": "Raw",
"usersScore": "90%",
"criticsScore": "77%"
}, {
"title": "The Wedding Plan",
"usersScore": "86%",
"criticsScore": "65%"
}, {
"title": "Maudie",
"usersScore": "88%",
"criticsScore": "92%"
}, {
"title": "Heal the Living (Réparer les vivants)",
"usersScore": "90%",
"criticsScore": "70%"
}, {
"title": "Lady Macbeth",
"usersScore": "89%",
"criticsScore": "72%"
}, {
"title": "The Exception (The Kaiser's Last Kiss)",
"usersScore": "76%",
"criticsScore": "67%"
}, {
"title": "Citizen Jane: Battle for the City",
"usersScore": "94%",
"criticsScore": "61%"
}, {
"title": "The Beguiled",
"usersScore": "78%",
"criticsScore": "50%"
}, {
"title": "The Big Sick",
"usersScore": "98%",
"criticsScore": "89%"
}, {
"title": "The Little Hours",
"usersScore": "77%",
"criticsScore": "53%"
}, {
"title": "A Ghost Story",
"usersScore": "91%",
"criticsScore": "66%"
}, {
"title": "The Hero",
"usersScore": "77%",
"criticsScore": "64%"
}, {
"title": "Megan Leavey",
"usersScore": "84%",
"criticsScore": "83%"
}, {
"title": "Band Aid",
"usersScore": "85%",
"criticsScore": "73%"
}, {
"title": "It Comes At Night",
"usersScore": "89%",
"criticsScore": "43%"
}, {
"title": "The Midwife (Sage femme)",
"usersScore": "86%",
"criticsScore": "82%"
}, {
"title": "Brawl in Cell Block 99",
"usersScore": "93%",
"criticsScore": "75%"
}, {
"title": "Gerald's Game",
"usersScore": "89%",
"criticsScore": "78%"
}]
答案 0 :(得分：1)
您实际需要的是组合两个数组，然后过滤它们以删除重复数据：
const merge = (data1, data2) => {
// keeps track of already existing titles to avoid duplicates
let existingIndexes = {};
// check the the arguments to make sure the code does not break
data1 = data1 instanceof Array ? data1 : [];
data2 = data2 instanceof Array ? data2 : [];
// return a concatenated and filtered copy result
return data1.concat(data2).filter((movie) => {
if (existingIndexes.hasOwnProperty(movie.title)) {
existingIndexes[movie.title] = true;
return true;
}
return false;
});
};
答案 1 :(得分：0)
这样的事情应该有用。
const getTitles = movies => movies.map(movie => movie.title);
const merge = (data1, data2) => {
const titles1 = getTitles(data1);
return data1.concat(data2.filter(movie => !titles1.includes(movie.title)));
}
答案 2 :(得分：0)
我最喜欢处理从数组中删除重复项的方法是使用Object作为字典然后转换回数组。这不是最有效的方法，但我喜欢代码最终的简单方式。我们需要一些方法来按键跟踪重复值（在这种情况下是你的电影标题），而Objects很容易为我们处理这个。
const merge = (key, arr1, arr2) => {
// Should probably check our parameters, but I'm leaving it out
// Our "dictionary" that will help prevent duplicates by using keys
let dictionary = {};
// Values in arr2 will overwrite values in arr1 if there is a duplicate
arr1.concat(arr2).forEach(item => {
dictionary[item[key]] = item;
// To always keep the first value, you could replace the previous line with this:
// dictionary[item[key]] = dictionary[item[key]] || item;
});
return Object.keys(dictionary).map(i => dictionary[i]);
};
答案 3 :(得分：0)
您可以使用array#reduce在两个阵列中制作独特的电影。
var data1 = [{"title":"Spider-Man: Homecoming","usersScore":"92%","criticsScore":"89%"},{"title":"Girls Trip","usersScore":"89%","criticsScore":"83%"},{"title":"Captain Underpants: The First Epic Movie (Captain Underpants)","usersScore":"87%","criticsScore":"62%"},{"title":"Guardians of the Galaxy Vol. 2","usersScore":"82%","criticsScore":"88%"},{"title":"Wonder Woman","usersScore":"92%","criticsScore":"89%"},{"title":"First They Killed My Father","usersScore":"88%","criticsScore":"83%"},{"title":"Baby Driver","usersScore":"93%","criticsScore":"87%"},{"title":"Demon","usersScore":"91%","criticsScore":"56%"},{"title":"The Music of Strangers: Yo-Yo Ma and the Silk Road Ensemble","usersScore":"84%","criticsScore":"85%"},{"title":"Colossal","usersScore":"80%","criticsScore":"59%"},{"title":"Certain Women","usersScore":"92%","criticsScore":"51%"},{"title":"Godzilla Resurgence (Shin Godzilla)","usersScore":"84%","criticsScore":"73%"},{"title":"My Cousin Rachel","usersScore":"76%","criticsScore":"47%"},{"title":"The Meyerowitz Stories (New and Selected)","usersScore":"93%","criticsScore":"84%"},{"title":"Raw","usersScore":"90%","criticsScore":"77%"},{"title":"The Wedding Plan","usersScore":"86%","criticsScore":"65%"},{"title":"Maudie","usersScore":"88%","criticsScore":"92%"},{"title":"Heal the Living (Réparer les vivants)","usersScore":"90%","criticsScore":"70%"},{"title":"Lady Macbeth","usersScore":"89%","criticsScore":"72%"},{"title":"The Exception (The Kaiser's Last Kiss)","usersScore":"76%","criticsScore":"67%"},{"title":"Citizen Jane: Battle for the City","usersScore":"94%","criticsScore":"61%"},{"title":"The Beguiled","usersScore":"78%","criticsScore":"50%"},{"title":"The Big Sick","usersScore":"98%","criticsScore":"89%"},{"title":"The Little Hours","usersScore":"77%","criticsScore":"53%"},{"title":"A Ghost Story","usersScore":"91%","criticsScore":"66%"},{"title":"The Hero","usersScore":"77%","criticsScore":"64%"},{"title":"Megan Leavey","usersScore":"84%","criticsScore":"83%"},{"title":"Band Aid","usersScore":"85%","criticsScore":"73%"},{"title":"It Comes At Night","usersScore":"89%","criticsScore":"43%"},{"title":"The Midwife (Sage femme)","usersScore":"86%","criticsScore":"82%"},{"title":"Brawl in Cell Block 99","usersScore":"93%","criticsScore":"75%"},{"title":"Gerald's Game","usersScore":"89%","criticsScore":"78%"}],
data2 = [{ "title": "The Midwife (Sage femme)","usersScore": "86%","criticsScore": "82%"}, {"title": "Brawl in Cell Block 99","usersScore": "93%", "criticsScore": "75%"}, {"title": "Gerald's Game","usersScore": "89%","criticsScore": "78%" }];
const merging = (data1, data2) => {
let unique = data1.concat(data2).reduce((map, movie) => {
return map[movie.title] = movie, map;
}, Object.create(null));
return Object.values(unique);
};
console.log(merging(data1,data2));.as-console-wrapper { max-height: 100% !important; top: 0; }