2018-10-10 22:03:03 +00:00
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---
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id: 587d7dab367417b2b2512b6e
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2021-03-15 20:01:16 +00:00
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title: 使用 every 方法检查数组中的每个元素是否符合条件
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2018-10-10 22:03:03 +00:00
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challengeType: 1
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2020-08-05 08:38:04 +00:00
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forumTopicId: 301312
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2021-01-13 02:31:00 +00:00
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dashedName: use-the-every-method-to-check-that-every-element-in-an-array-meets-a-criteria
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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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# --description--
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2021-03-15 20:01:16 +00:00
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`every` 方法用于检测数组中*所有*元素是否都符合指定条件。 如果所有元素满足条件,返回布尔值 `true`,反之返回 `false`。
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2020-12-16 07:37:30 +00:00
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2021-03-15 20:01:16 +00:00
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举个例子,下面的代码检测数组 `numbers` 的所有元素是否都小于 10:
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2020-08-05 08:38:04 +00:00
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```js
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var numbers = [1, 5, 8, 0, 10, 11];
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numbers.every(function(currentValue) {
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return currentValue < 10;
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});
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```
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2021-03-15 20:01:16 +00:00
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`every` 方法在这里会返回 `false`。
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2020-12-16 07:37:30 +00:00
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# --instructions--
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2018-10-10 22:03:03 +00:00
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2021-03-15 20:01:16 +00:00
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在 `checkPositive` 函数中使用 `every` 方法检查 `arr` 中是否所有元素都是正数。 函数应返回一个布尔值。
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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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# --hints--
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2018-10-10 22:03:03 +00:00
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2021-03-15 20:01:16 +00:00
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应使用`every`方法。
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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(code.match(/\.every/g));
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2018-10-10 22:03:03 +00:00
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```
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2021-03-15 20:01:16 +00:00
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`checkPositive([1, 2, 3, -4, 5])` 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.isFalse(checkPositive([1, 2, 3, -4, 5]));
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2018-10-10 22:03:03 +00:00
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```
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2021-03-15 20:01:16 +00:00
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`checkPositive([1, 2, 3, 4, 5])` 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.isTrue(checkPositive([1, 2, 3, 4, 5]));
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```
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2018-10-10 22:03:03 +00:00
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2021-03-15 20:01:16 +00:00
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`checkPositive([1, -2, 3, -4, 5])` 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.isFalse(checkPositive([1, -2, 3, -4, 5]));
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2018-10-10 22:03:03 +00:00
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```
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2020-08-05 08:38:04 +00:00
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2021-01-13 02:31:00 +00:00
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# --seed--
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## --seed-contents--
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```js
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function checkPositive(arr) {
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// Only change code below this line
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// Only change code above this line
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}
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checkPositive([1, 2, 3, -4, 5]);
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```
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2020-12-16 07:37:30 +00:00
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# --solutions--
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2021-01-13 02:31:00 +00:00
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```js
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function checkPositive(arr) {
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// Only change code below this line
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return arr.every(num => num > 0);
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// Only change code above this line
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}
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checkPositive([1, 2, 3, -4, 5]);
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```
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