2018-10-10 22:03:03 +00:00
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---
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id: 587d7dbf367417b2b2512bba
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2020-12-16 07:37:30 +00:00
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title: 使用 @each 遍历列表中的项目
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2018-10-10 22:03:03 +00:00
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challengeType: 0
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2020-09-07 08:11:08 +00:00
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forumTopicId: 301461
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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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2020-09-07 08:11:08 +00:00
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2020-12-16 07:37:30 +00:00
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最后一个挑战显示了`@for`指令如何使用起始值和结束值循环一定次数。Sass 还提供`@each`指令,该指令循环遍历列表或映射中的每个项目。 在每次迭代时,变量将从列表映射赋值给当前值。
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2020-09-07 08:11:08 +00:00
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```scss
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@each $color in blue, red, green {
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.#{$color}-text {color: $color;}
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}
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```
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map 的语法略有不同。这是一个例子:
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```scss
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$colors: (color1: blue, color2: red, color3: green);
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@each $key, $color in $colors {
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.#{$color}-text {color: $color;}
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}
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```
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2020-12-16 07:37:30 +00:00
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请注意,需要`$key`变量来引用 map 中的键。否则,编译后的 CSS 将包含`color1`,`color2`...... 以上两个代码示例都转换为以下 CSS:
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2020-09-07 08:11:08 +00:00
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```scss
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.blue-text {
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color: blue;
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}
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.red-text {
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color: red;
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}
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.green-text {
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color: green;
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}
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```
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2020-12-16 07:37:30 +00:00
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# --instructions--
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2020-09-07 08:11:08 +00:00
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2020-12-16 07:37:30 +00:00
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编写一个`@each`指令,通过一个列表:`blue,black,red`并将每个变量分配给`.color-bg`class, 其中每个项目的“颜色”部分都会发生变化。 每个 class 都应该将`background-color`设置为相应的颜色。
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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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你的代码应使用`@each`指令。
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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(/@each /g));
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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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`.blue-bg`class 背景色应为蓝色。
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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($('.blue-bg').css('background-color') == 'rgb(0, 0, 255)');
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2018-10-10 22:03:03 +00:00
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```
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2020-12-16 07:37:30 +00:00
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`.black-bg`class 背景色应为黑色。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert($('.black-bg').css('background-color') == 'rgb(0, 0, 0)');
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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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`.red-bg`class 背景色应为红色。
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2020-09-07 08:11:08 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert($('.red-bg').css('background-color') == 'rgb(255, 0, 0)');
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2020-09-07 08:11:08 +00:00
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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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