2018-10-10 22:03:03 +00:00
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---
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id: 8d1323c8c441eddfaeb5bdef
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2020-12-16 07:37:30 +00:00
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title: 创建一个Set类
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2018-10-10 22:03:03 +00:00
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challengeType: 1
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videoUrl: ''
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---
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2020-12-16 07:37:30 +00:00
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# --description--
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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在接下来的几个练习中,我们将创建一个函数来模拟一个名为“Set”的数据结构。 Set类似于数组,但不能包含重复值。 Set的典型用途是简单地检查项目是否存在。这可以用对象实现,例如:
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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> var set = new Object();
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> set.foo = true;
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> //看看我们的集合中是否存在foo:
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> console.log(set.foo)// true
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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在接下来的几个练习中,我们将从头开始构建一个全功能的Set。对于本练习,只要该值中尚不存在该值,就创建一个将值添加到set集合的函数。例如:
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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> this.add = function(element){
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> //一些代码来为集合添加值
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> }
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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如果成功添加该值,则该函数应返回`true`否则返回`false` 。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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# --hints--
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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您的`Set`类应该有一个`add`方法。
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert(
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(function () {
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var test = new Set();
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return typeof test.add === 'function';
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})(),
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'Your <code>Set</code> class should have an <code>add</code> method.'
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);
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2018-10-10 22:03:03 +00:00
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```
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2020-12-16 07:37:30 +00:00
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您的`add`方法不应添加重复值。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(
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(function () {
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var test = new Set();
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test.add('a');
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test.add('b');
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test.add('a');
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var vals = test.values();
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return vals[0] === 'a' && vals[1] === 'b' && vals.length === 2;
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})(),
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'Your <code>add</code> method should not add duplicate values.'
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);
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```
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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成功添加值后, `add`方法应返回`true` 。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert(
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(function () {
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var test = new Set();
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var result = test.add('a');
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return result != undefined && result === true;
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})(),
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'Your <code>add</code> method should return <code>true</code> when a value has been successfully added.'
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);
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```
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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`add`重复值时, `add`方法应返回`false` 。
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert(
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(function () {
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var test = new Set();
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test.add('a');
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var result = test.add('a');
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return result != undefined && result === false;
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})(),
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'Your <code>add</code> method should return <code>false</code> when a duplicate value is added.'
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);
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2018-10-10 22:03:03 +00:00
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```
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2020-08-13 15:24:35 +00:00
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2020-12-16 07:37:30 +00:00
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# --solutions--
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