如何使用數組條件過濾數組

Question

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

我想用學生數組過濾（或映射，forEach隨便什么）人員數組。 學生數組是動態的，因此可以更改其長度。

有任何想法嗎？

Answer 1

可以使用filter和some來完成。

 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 // (eg "Malcom" !== "malcom"). // It would be: persons.filter(person => students.some(student => student.toLowerCase() === person.firstname.toLowerCase())) 

Answer 2

您可以使用Set和Array#filter 。

 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

您應該能夠通過檢查他們的firstname是否在students數組中來過濾該數組：

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

Answer 4

為此，您可以使用filter()和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);