[英]Comparing and Filtering two arrays
我一直在嘗試實現一個 function,其中有兩個 arrays,
array1的元素用作過濾掉array2中元素的條件。
例如:
array1= [apple, grapes, oranges]
array2= [potato, pears, grapes, berries, apples, oranges]
在輸入 function 后,array2 應該有這樣的元素:
filter_twoArrays(array1,array2)
array2= [grapes, apples, oranges]
我嘗試了以下代碼,使用 for 循環和 array.splice(),但我看到的問題是,當我使用 splice 方法時,它似乎改變了 for 循環中 array2 的長度:
function filter_twoArrays(filter,result){
for(i=0; i< filter.length; i++){
for(j=0; j< result.length; j++){
if(filter[i] !== result[j]){
result.splice(j,1)
}
}
}
任何關於如何改進過濾器的輸入將不勝感激 function
干杯!
您可以使用過濾器如下
var array1 = ['apples', 'grapes', 'oranges', 'banana'], array2 = ['potato', 'pears', 'grapes', 'berries', 'apples', 'oranges']; var intersection = array1.filter(function(e) { return array2.indexOf(e) > -1; }); console.log(intersection);
也可以在 Array 原型上添加這個方法,直接在數組上調用
Array.prototype.intersection = function(arr) { return this.filter(function(e) { return arr.indexOf(e) > -1; }); }; var array1 = ['apples', 'grapes', 'oranges', 'banana'], array2 = ['potato', 'pears', 'grapes', 'berries', 'apples', 'oranges']; var intersection = array1.intersection(array2); console.log(intersection);
嗨,這是函數 array_intersect php 的移植。 應該對你有好處http://phpjs.org/functions/array_intersect/
function array_intersect(arr1) {
// discuss at: http://phpjs.org/functions/array_intersect/
// original by: Brett Zamir (http://brett-zamir.me)
// note: These only output associative arrays (would need to be
// note: all numeric and counting from zero to be numeric)
// example 1: $array1 = {'a' : 'green', 0:'red', 1: 'blue'};
// example 1: $array2 = {'b' : 'green', 0:'yellow', 1:'red'};
// example 1: $array3 = ['green', 'red'];
// example 1: $result = array_intersect($array1, $array2, $array3);
// returns 1: {0: 'red', a: 'green'}
var retArr = {},
argl = arguments.length,
arglm1 = argl - 1,
k1 = '',
arr = {},
i = 0,
k = '';
arr1keys: for (k1 in arr1) {
arrs: for (i = 1; i < argl; i++) {
arr = arguments[i];
for (k in arr) {
if (arr[k] === arr1[k1]) {
if (i === arglm1) {
retArr[k1] = arr1[k1];
}
// If the innermost loop always leads at least once to an equal value, continue the loop until done
continue arrs;
}
}
// If it reaches here, it wasn't found in at least one array, so try next value
continue arr1keys;
}
}
return retArr;
}
你可以使用some
,像這樣:
let newArray = array2.filter(
(array22) => !array1.some((array11) => array11.id === array22._id));
由於您已在此處標記 javascript,因此這是解決方案。
function f1(x, y) {
var t = y.slice(0);
var r = [];
for (var i = 0; i < x.length; i++) {
for (var j = 0; j < y.length; j++) {
if (x[i] === y[j]) {
[].push.apply(r, t.splice(j, 1));
}
}
}
console.log(r)
y.length = 0;
[].push.apply(y, r);
}
這是一種基於您的代碼的簡單方法
function array_filter(filter, result) {
var filterLen = filter.length;
var resultLen = result.length;
for (i = 0; i < resultLen; i++) {
for (j = 0; j < filterLen; j++) {
if (!contains(filter, result[i]))
result.splice(i, 1);
}
}
}
//Return boolean depending if array 'a' contains item 'obj'
function contains(array, value) {
for (var i = 0; i < array.length; i++) {
if (array[i] == value) {
return true;
}
}
return false;
}
標記要通過delete result[index]
過濾掉的項目,根據需要對其進行操作。
JavaScript
window.onload = runs;
function runs() {
var array1 = ["apples", "grapes", "oranges"];
var array2 = ["potato", "pears", "grapes", "berries", "apples", "oranges"];
var result = filter_twoArrays(array1, array2);
function filter_twoArrays(filter, result) {
var i = 0,
j = 0;
for (i = 0; i < result.length; i++) {
var FLAG = 0;
for (j = 0; j < filter.length; j++) {
if (filter[j] == result[i]) {
FLAG = 1;
}
}
if (FLAG == 0) delete result[i];
}
return result;
}
var body = document.getElementsByTagName("body")[0];
var i = 0;
for (i = 0; i < result.length; i++) {
if (result[i] !== undefined)
body.innerHTML = body.innerHTML + result[i] + " ";
}
}
您可以使用
const arr1 = [1, 2, 3];
const arr2 = [2, 3];
arr1.filter(e => arr2.indexOf(e) > -1 ? false : true); // [1]
一周前來到這里尋找解決此類問題的方法,但很遺憾我無法得到我想要的東西,但現在我以更簡單的方式解決了問題。 使用箭頭函數、 .filter()方法和.includes()方法。
聲明一個接受兩個參數的箭頭函數:
const filterTwoArrays = (string1, string2) => string1.filter(item => string2.includes(item));
console.log(filterTwoArrays(array1, array2)).
const func = array1.filter(item => array2.includes(item));
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