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(一个关于filter的问题)实现一个摧毁(destroyer)函数,第一个参数是待摧毁的数组,其余的参数是待摧毁的值

Altcademy Team wrote on 7 February 2018

问题是:实现一个摧毁(destroyer)函数,第一个参数是待摧毁的数组,其余的参数是待摧毁的值。

一开始是这样的:
function destroyer(arr) { for(var i=1;i<arguments.length;i++){ arr=arr.filter(function(x){return x!==arguments[i];}); } return arr; } destroyer([1, 2, 3, 1, 2, 3], 2, 3); //结果返回了原数组

后来声明了一个变量存储argumetns[i]就没问题了,Why?
function destroyer(arr) { for(var i=1;i<arguments.length;i++){ var number=arguments[i]; arr=arr.filter(function(x){return x!==number;}); } return arr; } destroyer([1, 2, 3, 1, 2, 3], 2, 3);

Hi @GreatAuk, you can have a look at the following repl https://repl.it/Cn6r

What is happening is the first arguments is the arguments of the destroyer function, the second arguments is the arguments of the filter callback function.

function destroyer(arr) { for(var i=1;i<arguments.length;i++){ console.log('arguments1', arguments) // => arguments1 { '0': [ 1, 2, 3, 1, 2, 3 ], '1': 2, '2': 3 } arr = arr.filter(function(x){ console.log('arguments2', arguments); // => argument2 { '0': 1, '1': 0, '2': [ 1, 2, 3, 1, 2, 3 ] } return x!==arguments[i]; }); } return arr; } destroyer([1, 2, 3, 1, 2, 3], 2, 3); //结果返回了原数组

But you actually want to compare x with the elements of arr so you have to assign it for each step of the for loop.

for(var i=1;i<arguments.length;i++){ var number = arguments[i]; // assign argument element to number so it can be used in the filter callback function arr = arr.filter(function(x){return x!==number;}); }

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