在JavaScript中使用filter（）的4個(gè)實(shí)用案例
1、刪除重復(fù)的值
const numbers = [3, 12, 54, 12, 4, 4, 3, 12, 16];const filteredNumbers = numbers.filter((number, index) => numbers.indexOf(number) === index);console.log(filteredNumbers); // [3, 12, 54, 4, 16]
2、刪除無效值
const people = [{ name: ‘Amy’, gender: ‘female’, age: ‘28’ },{ name: ‘James’, gender: ‘male’, age: 13 },{ name: ‘Victor’, gender: ‘male’, age: null },{ name: ‘David’, gender: ‘male’, age: 28 },{ name: ‘Simon’, gender: ‘male’, age: undefined },{ name: ‘Anna’, gender: ‘female’, age: 21 },{ name: ‘Jane’, gender: ‘female’, age: NaN }];const filteredPeople = people.filter(person => person.age !== undefined && typeof person.age === ‘number’ && !isNaN(person.age));console.log(filteredPeople);// [{ name: ‘James’, gender: ‘male’, age: 13 }, { name: ‘David’, gender: ‘male’, age: 28 }, { name: ‘Anna’, gender: ‘female’, age: 21 }]
3、過濾數(shù)字?jǐn)?shù)組
const numbers = [23, 54, 1, 3, 72, 28];const oddNumbers = numbers.filter(number => number % 2 !== 0);console.log(oddNumbers); // [23, 1, 3]
const isPrime = number => {if (number === 1) return false;if (number === 2) return true;for (let i = 2; i < number; i++) {if (number % i === 0) return false;}return true;}const numbers = [23, 54, 1, 3, 72, 28];const oddNumbers = numbers.filter(isPrime);console.log(oddNumbers); // [23, 3]
4、過濾對象數(shù)組
const people = [{ name: ‘Amy’, gender: ‘female’, age: 28 },{ name: ‘James’, gender: ‘male’, age: 13 },{ name: ‘Victor’, gender: ‘male’, age: 17 },{ name: ‘David’, gender: ‘male’, age: 28 },{ name: ‘Simon’, gender: ‘male’, age: 33 }];const filteredPeople = people.filter(person => person.age > 18);console.log(filteredPeople);// [{ name: ‘Amy’, gender: ‘female’, age: 28 }, { name: ‘David’, gender: ‘male’, age: 28 }, { name: ‘Simon’, gender: ‘male’, age: 33 }]
const people = [{ name: ‘Amy’, gender: ‘female’, age: 28 },{ name: ‘James’, gender: ‘male’, age: 13 },{ name: ‘Victor’, gender: ‘male’, age: 17 },{ name: ‘David’, gender: ‘male’, age: 28 },{ name: ‘Simon’, gender: ‘male’, age: 33 }];const filteredPeople = people.filter(person => person.age > 18 && person.gender === ‘female’);console.log(filteredPeople);// [{ name: ‘Amy’, gender: ‘female’, age: 28 }]
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