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R Error: `n()` must only be used inside dplyr verbs

The code in which I am getting the error. numCrimesByLSOA<-crimes %>% select(LSOA.code, LSOA.name, Crime.type) %>% group_by(LSOA.code) %>% summarise(Num.crimes=n())...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - Angular 11 - Add icons with different styles to a custom button component

In my Angular 11 App I've implemented a custom button component. For styling I use TailwindCSS and ... .com/edit/angular-ivy-6gpcby?file=src%2Fapp%2Fbutton%2Fbutton.component.ts...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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800 views

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typescript - iconSet[key].split is not a function

I'm writing a Vue.js application using ts and Vuetify. I want to add a new prototype to all objects. declare global { ... that I made a prototype for all arrays and it works fine...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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xlsxwriter - select cells by using the hlookup python

I have two worksheet in excel like this , and I want to select cells by using the Hlookup with python: data 1: id D1A ... B 7 2 Any help on this would be appreciated. thank you....

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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请问 socket 编程如何深入学习呢？

大佬们，我这边了解了基础的 socket 编程，看了网上的一些教程，也使用 go socket 开发了一个简单的聊天室，但是我觉得对于 socket 编程还是学得很肤浅，现在想深入学习 socket 编程，日后开发 IM 软件时用上，各位有什么学习案例或书籍等介绍吗？或者其他学习方法推荐？...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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unity3d - Why my onTrigger is trigering 3 times, even Destroying the other object in the first line?

My ontriggerenter2D is triggering 3 times(instantiating 3 objects), even with me destroying the other object before ... .transform); _playerDamager.isPlayerShielded = true; } }...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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CPU的功能是计算与控制，那么8086CPU内部结构中，哪里体现了控制功能？

黄色的框是8086 CPU内部结构。中间蓝色的竖线将CPU分为左右两块。左边是EU执行单元，也即是计算功能，右边是BIU总线接口单元，体现了运算器与存储器之间的联系。体现控制功能在哪里呢？我怎么看不出来呢？...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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多表联合查询优化

explain select SQL_CALC_FOUND_ROWS * from task a,user b ,task_project c,task_platform d where a.user_id = b.id and a.project_id = c.id and ... 像出在 c.platform_id = d.id 与a表无关联求优化 ...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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python - How to preprocess a single image for keras pretrained model input with keras.preprocessing.image.load_img()

preprocessed image with Image library data = np.ndarray(shape=(1, 224, 224, 3), dtype=np.float32) I_image = Image.open('2. ... k_data[0] = input_arr k_data.shape (1, 224, 224, 3)...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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420 views

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前端项目js压缩成一行性能有很大提升吗？

...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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219 views

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Generate lazy Stream from method call in Java

For example I have a method List<A> getA(), and I want to get a Stream<A> elements of which are the ... stream); but maybe someone knows a more convenient approach. Thank you....

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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171 views

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nuxt服务端怎么获取用户的remote_addr

服务器是nginx nginx的配置如下我在axios的拦截器里面增加了一个自定义头u-host用于获取用户的remote_addr，真实环境下我总是获取不到我想要的客户端ip 这是我python后端程序获取客户端的ip 我不知道接下来该怎么做才能在nuxt服务端渲染数据的时候还能获取到客户的真实ip，于是求助于社区...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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569 views

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如何理解网络传输协议？

以前一直做PHP，只处理HTTP超文本数据，后来转底层开发语言，对于TCP数据的传输不太理解，比如iOS客户端发送了数据包，到了Go的服务端，却可以解出数据类型来判断使用哪种方法进行处理，这里面是 ... 157 249 255 255 255 255 1 18 12 24 9 40 161 138 220 222 223 252 255 207 77]...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1 answer

vue二维码扫描把当前用户数据传给注册页面

这种写法，我扫描直接undefined，也许是因为我还没有上传服务器，所以扫不出来手机扫出来是这样的： http://192.168.3.159:8877/register?name=undefined&code=undefined 我二维码页面写的是这样子 ... ////////////////// [凯迪Wen]说的写法，用上后就只会放大了 ...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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el-drawer左对齐设置

使用el-drawer做了一个高级查询的抽屉，页面分成了两个部分，当左侧部分展开时抽屉显示正常。但是当用点击事件把左侧部分关闭后，这个抽屉还是根据初始的右侧去显示设置抽屉的宽度无法实现，怎么让抽屉在左侧部分关闭时让它以当前右侧部分去左对齐，而不是以起始的部分左对齐...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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vuecli3.0安装elementui后全局引入报错？

就很烦，我本意是像搭cli3.0版本的（更正一下，是3.0版本，因为之前网上很多将2.0和3.0版本的给弄模糊了，我以为不是3.0版本的，又不认识这个版本的引入方式，就以为是4.0了），但是不知道为什么每次安装出来就是这种的有没有大佬知道该怎么解决这个问题啊问题解决了——老老实实滚回去搞2.0版本的了...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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求解：vue如何遍历数组对象中的数组。

要遍历的数据：这只展示了第一层 list: [ { id: 1, name: "第一层", child: [], }, { id: 1, name: "第一层", child: [ { id: 2, name: "第一层第二层" ... : "第一层第二层第三层", child: [], }, ], }, ], }, ], foreach写的方法，...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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regex - In Perl how to move folder in which folder name has junk letters?

How to move the folder, in which folder name containing junk characters. (ex:Theoretical Analysis_Ferda ?-zdemir S??nmez). ... & ?). Please help me with this. Thanks in advance...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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java - Is defining a class attribute in a class function accepted?

I have an object instantiated and I would like to call a function of this object that going to initialize an attribute of ... it make sense to do that in the constructor here ?...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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377 views

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typescript以下两条特性是什么意思？

JavaScript 和 TypeScript 的主要差异 TypeScript 可以使用 JavaScript 中的所有代码和编码概念，TypeScript 是为了使 JavaScript 的开发变得更加容易而创建的例如，TypeScript 使用类型和接 ... 最后两条是什么意思？ javascript里不是也有class的概念嘛？模块是是意思？...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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479 views

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react native 封装的请求工具里如何改变redux状态的值？

react native 封装的请求工具里如何改变redux状态的值，在请求响应后需要根据判断改变登录弹窗的显示状态，状态好像是改变了，但是组件内没有监听到状态的变化...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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267 views

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python - How to swap two widgets' x position in tkinter?

I need to create a function that takes as a parameter two widgets and the frame they are placed. I want to swap their ... the right way of doing this? Is this the right approach?...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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484 views

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vue import异步组件失效

（）=>import（）这种写法就无效但是用require.ensure就可以版本没有问题，支持import，不知道什么地方影响了......

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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Linked List - remove duplicates algorithm in C#/Java

I am studying Data Structures and Algorithms in C#/Java. After encountering a solution to the problem of Linked List ... reference, but I cannot see how it is actually modified....

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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python - How to cast string to byte like object

I am trying to make a python script that encodes any file into a txt file. So far I can encode an input file into a ... , on a side note: does "rb" include metadata, title, etc?...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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408 views

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python的URL路由怎样配置成：文章详情页的标题做为网址URL？

请问，URL配置的问题。我想以文章详情页的标题做为网址URL，在URL配置正则. 但不生效。如何操作，有高手解释一下吗？比如：详情页的标题是：好好学习，天天向上我想打开的URL是：/detail/好好学习天天向上类似这样子。就像博客系统或wordpress那样。以文章名作为URL 求解。...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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288 views

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mongorestore 恢复失败

如下，Mac os x系统上备份的数据想恢复到云服务器上的mongo容器内，其他几个库恢复正常，这个库是最近新建的，恢复失败了 mongorestore --authenticationDatabase admin -u admin -- ... . mac系统mongodb版本为4.0.4, 云服务器与docker容器mongo的版本都是4.4.1...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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792 views

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node.js - npm package (PeerJS) installed but not recognized in command line

I'm trying to use PeerJS in the command line after I've installed it using npm i -g peerjs and I can ... help on getting this command working would be greatly appreciated. Thanks....

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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