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问题 I'm trying to formalize each integer as an equivalence class of pairs of natural numbers, where the first component is the positive part, and the second component is the negative part. Definition integer : Type := prod nat nat. I want to define a normalization function where positives and negatives cancel as much as possible. Fixpoint normalize (i : integer) : integer := let (a, b) := i in match a with | 0 => (0, b) | S a' => match b with | 0 => (S a', 0) | S b' => normalize (a', b') end end.

问题 I just started to use firebase Functions and I am new to the node.js environment, can somebody tell how to iterate through a child node and get the child values. 回答1: see this example: const parentRef = admin.database().ref("path"); return parentRef.once('value').then(snapshot => { const updates = {}; snapshot.forEach(function(child) { updates[child.key] = null; }); return parentRef.update(updates); }); 回答2: Have you looked through the Cloud Functions for Firebase Samples? They contain many

问题 I am working on angular project and came to a situation where i have series of div in a row and when user clicks on any div he should be able to move from one div to another using arrow key. Please help. I tried using keypress event but it didn't helped me. Tried finding out similar questions on stackoverflow but all answers where into jquery and i need it in in typescript. moveCell(e){ console.log(e); } .container{ width: 100%; } .cell{ width: 100px; float:left; } .cell:hover, .cell:focus{

问题 I have a webapp using Spring-MVC built with Maven. When I generate the JAR file the app start just fine. The controller is execute but when I reach this part: @RequestMapping(value = "/test-block", method = RequestMethod.GET) public ModelAndView block(Model model) { return new ModelAndView("templates/test-block"); } I get this error: There was an unexpected error (type=Not Found, status=404). /WEB-INF/templates/test-block.jsp Note that debugging or running in the IDE works fine. My folder:

问题 I'm trying to pass an id in my routerLink, how could I concatenate it? <a routerLink="['/details', {{data.id}}]"> </a> doesnt work. Do you have solutions? Thanks in advance 回答1: There you go. <a [routerLink]="['/details', data.id]"> Link </a> 回答2: Parameters go as second item in the array syntax to router link, like this: [routerLink]="['/details', data.id] Read more here 来源： https://stackoverflow.com/questions/53523472/angular-variable-into-routerlink

问题 so in my Vue-project I basically have two pages/components that will be shown with the use of vue-router depending on the url. I can switch between those pages/components via a button. I am also using vuex for the management of some data. Now I included a switch in one of the components to toggle between a dark and a light theme from vuetify. In the template for this component I do: <v-switch label="Toggle dark them" @change="toggleDarkTheme()" ></v-switch> And in the function that gets

问题 I'm trying to pass an id in my routerLink, how could I concatenate it? <a routerLink="['/details', {{data.id}}]"> </a> doesnt work. Do you have solutions? Thanks in advance 回答1: There you go. <a [routerLink]="['/details', data.id]"> Link </a> 回答2: Parameters go as second item in the array syntax to router link, like this: [routerLink]="['/details', data.id] Read more here 来源： https://stackoverflow.com/questions/53523472/angular-variable-into-routerlink

问题 I want to iterate through a pcap file packet for packet using python/scapy. The file has multiple protocols. Current the iteration is protocol-specific, so the iteration makes a "jump" if the next packet is from another protocol. I don't know why it goes like this at the moment. I want packet for packet, no matter what protocol. little example: data = 'new.pcap' zz = rdpcap(data) sessions = zz.sessions() for session in sessions: for packet in sessions[session]: eth_src = packet[Ether].src eth

问题 I'm wondering if there's an efficient way to get X number of rows below and above a subset of rows. I've created a basic implementation below, but I'm sure there's a better way. The subset that I care about is buyindex, which is the indices of rows that have the buy signal. I want to get several rows above and below the sellindex to verify that my algorithm is working correctly. How do I do it in an efficient way? My way seems roundabout. buyindex = list(data2[data2['buy'] == True].index)

问题 I want to iterate through a pcap file packet for packet using python/scapy. The file has multiple protocols. Current the iteration is protocol-specific, so the iteration makes a "jump" if the next packet is from another protocol. I don't know why it goes like this at the moment. I want packet for packet, no matter what protocol. little example: data = 'new.pcap' zz = rdpcap(data) sessions = zz.sessions() for session in sessions: for packet in sessions[session]: eth_src = packet[Ether].src eth