配列条件で配列をフィルタリングする方法

Question

var students = ["Malcom", "Jayne"]; 
var persons = [ 
    {firstname : "Malcom", lastname: "Reynolds"}, 
    {firstname : "Kaylee", lastname: "Frye"}, 
    {firstname : "Jayne", lastname: "Cobb"} 
]; 

私は学生配列のフィルタ配列を作成したいと思います。 生徒配列は動的なので、長さを変更できます。

アイデア？

Answer 1

を使用することができます。

var students = ["Malcom", "Jayne"]; 
 

 
var persons = [ 
 
    {firstname : "Malcom", lastname: "Reynolds"}, 
 
    {firstname : "Kaylee", lastname: "Frye"}, 
 
    {firstname : "Jayne", lastname: "Cobb"} 
 
]; 
 

 
console.log(persons.filter(person => students.some(student => student == person.firstname))) 
 

 
// An advice, maybe you want to put everything to lower case 
 
// to prevent a wrong result because of case mismatch 
 
// (e.g. "Malcom" !== "malcom"). 
 
// It would be: 
 

 
persons.filter(person => students.some(student => student.toLowerCase() === person.firstname.toLowerCase()))

Answer 2

SetとArray#filterを使用できます。

var students = ["Malcom", "Jayne"], 
 
    persons = [{ firstname: "Malcom", lastname: "Reynolds" }, { firstname: "Kaylee", lastname: "Frye" }, { firstname: "Jayne", lastname: "Cobb" }], 
 
    result = persons.filter(function (a) { 
 
     return this.has(a.firstname); 
 
    }, new Set(students)); 
 

 
console.log(result);

ES6

var students = ["Malcom", "Jayne"], 
 
    persons = [{ firstname: "Malcom", lastname: "Reynolds" }, { firstname: "Kaylee", lastname: "Frye" }, { firstname: "Jayne", lastname: "Cobb" }], 
 
    result = persons.filter((set => a => set.has(a.firstname))(new Set(students))); 
 

 
console.log(result);

Answer 3

そのfirstnameがstudents配列である場合は、チェックすることで、配列をフィルタリングすることができるはずです。

このために

persons.filter(function(person) { return students.indexOf(person.firstname) >= 0 }); 

Answer 4

あなたはそれがsomeとともにfilterで行うことができますfilter()とincludes()

var students = ["Malcom", "Jayne"]; 
 
var persons = [ 
 
    {firstname : "Malcom", lastname: "Reynolds"}, 
 
    {firstname : "Kaylee", lastname: "Frye"}, 
 
    {firstname : "Jayne", lastname: "Cobb"} 
 
]; 
 

 
var r = persons.filter(function(o) { 
 
    return students.includes(o.firstname); 
 
}); 
 

 
console.log(r)

Answer 5

var students = ["Malcom", "Jayne"]; 
var persons = [ 
    {firstname : "Malcom", lastname: "Reynolds"}, 
    {firstname : "Kaylee", lastname: "Frye"}, 
    {firstname : "Jayne", lastname: "Cobb"} 
]; 
var filteredPersons = persons.filter(person => students.indexOf(person.firstname) > -1);