vue学习(五)基础入门-基础知识(7)

﹏ヽ暗。殇╰゛Y 2023-05-29 05:13 18阅读 0赞

v-for

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70 1][]

v-for 遍历对象

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70 2][]

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组件的key属性![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70 4][]

当Vue用 v-for 正在更新已渲染过的元素列表是，它默认用“就地复用”策略。如果数据项的顺序被改变，Vue将不是移动DOM元素来匹配数据项的改变，而是简单复用此处每个元素，并且确保它在特定索引下显示已被渲染过的每个元素。

为了给Vue一个提示，以便它能跟踪每个节点的身份，从而重用和重新排序现有元素，你需要为每项提供一个**唯一 key 属性**。key属性的类型只能为 string或者number类型。

vue中列表循环需加:key="唯一标识" 唯一标识可以是item里面id index等，因为vue组件高度复用增加**Key可以标识组件的唯一性**，为了更好地区别各个组件 key的作用主要是为了高效的更新虚拟DOM

[Vue——v-for中 key 属性的使用][Vue_v-for_ key]

[关于Vue v-for中的:key作用][Vue v-for_key]

[vue中使用v-for时为什么不能用index作为key？][vue_v-for_index_key]

[为什么vue中的v-for key值不推荐使用index][vue_v-for key_index]

Vue响应式 数组方法

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70 5][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70 6][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70 7][]

注:通过索引值修改数组中的元素不是响应式的

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20191104154714731.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU=,size_16,color_FFFFFF,t_70
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[Vue_v-for_ key]: https://www.cnblogs.com/yangpeixian/p/11707069.html
[Vue v-for_key]: https://www.jianshu.com/p/96adab2c6d48?from=timeline&isappinstalled=0
[vue_v-for_index_key]: https://blog.csdn.net/aihuanhuan110/article/details/98223011
[vue_v-for key_index]: https://segmentfault.com/a/1190000019128999?utm_source=tag-newest
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU_size_16_color_FFFFFF_t_70 5]: https://img-blog.csdnimg.cn/20191104161831598.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1eXhpbnU=,size_16,color_FFFFFF,t_70
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