lookup

What is the best way to create a whois lookup? [closed]

由 孤街醉人 提交于 2019-11-27 12:57:16
问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 7 years ago . I want add a domain registration in a website written with PHP. So I need a whois lookup service. What do I need to do? What's are its steps? Do I need a database, API or ... ? Help me please 回答1: I cannot speak

Create sine lookup table in C++

由 这一生的挚爱 提交于 2019-11-27 12:24:30
问题 How can I rewrite the following pseudocode in C++? real array sine_table[-1000..1000] for x from -1000 to 1000 sine_table[x] := sine(pi * x / 1000) I need to create a sine_table lookup table. 回答1: You can reduce the size of your table to 25% of the original by only storing values for the first quadrant, i.e. for x in [0,pi/2]. To do that your lookup routine just needs to map all values of x to the first quadrant using simple trig identities: sin(x) = - sin(-x), to map from quadrant IV to I

Decision between storing lookup table id's or pure data

由 早过忘川 提交于 2019-11-27 10:58:36
问题 I find this comes up a lot, and I'm not sure the best way to approach it. The question I have is how to make the decision between using foreign keys to lookup tables, or using lookup table values directly in the tables requesting it, avoiding the lookup table relationship completely. Points to keep in mind: With the second method you would need to do mass updates to all records referencing the data if it is changed in the lookup table. This is focused more towards tables that have a lot of

Which is faster, Hash lookup or Binary search?

由 元气小坏坏 提交于 2019-11-27 10:29:16
When given a static set of objects (static in the sense that once loaded it seldom if ever changes) into which repeated concurrent lookups are needed with optimal performance, which is better, a HashMap or an array with a binary search using some custom comparator? Is the answer a function of object or struct type? Hash and/or Equal function performance? Hash uniqueness? List size? Hashset size/set size? The size of the set that I'm looking at can be anywhere from 500k to 10m - incase that information is useful. While I'm looking for a C# answer, I think the true mathematical answer lies not

Checking if Date is Between two Dates in R

由 只愿长相守 提交于 2019-11-27 09:42:15
I have two large datasets, df1 and df2. The first dataset, df1, contains the columns 'ID' and 'actual.data'. df1 <- data.frame(ID=c(1,1,1,2,3,4,4), actual.date=c('10/01/1997','2/01/1998','5/01/2002','7/01/1999','9/01/2005','5/01/2006','2/03/2003')); dcis <- grep('date$',names(df1)); df1[dcis] <- lapply(df1[dcis],as.Date,'%m/%d/%Y'); df1; ID actual.date 1 1 1997-10-01 2 1 1998-02-01 3 1 2002-05-01 4 2 1999-07-01 5 3 2005-09-01 6 4 2006-05-01 7 4 2003-02-03 The second dataset, df2, contains two date fields, 'before,date' and 'after.date', which represent a start and end date, respectively: df2 <

MongoDB add to joining collection field from base one

由 自作多情 提交于 2019-11-27 08:33:46
问题 I have two collections: Games with schema: _id: ObjectId('gameId'), questions: [ { position: 1, question_id: ObjectId('baz') }, { position: 2, question_id: ObjectId('ban') }, ] Questions with schema: _id: ObjectId('baz'), text: 'FooBar' And now I'd like to join questions to games with adding to each question record value of question_position . So, I have query like this: db.games.aggregate([ { $lookup: { from: 'questions', localField: 'questions.question_id', foreignField: '_id', as:

Working with dictionaries/lists in R

由 喜你入骨 提交于 2019-11-27 05:01:29
问题 I have trivial question: I couldn't find a dictionary data structure in R, so I used list instead (like "word"->number) So, right now I have problem how to get the list of keys. Anybody knows? 回答1: Yes, the list type is a good approximation. You can use names() on your list to set and retrieve the 'keys': > foo <- vector(mode="list", length=3) > names(foo) <- c("tic", "tac", "toe") > foo[[1]] <- 12; foo[[2]] <- 22; foo[[3]] <- 33 > foo $tic [1] 12 $tac [1] 22 $toe [1] 33 > names(foo) [1] "tic

Mongodb Join on _id field from String to ObjectId

由 柔情痞子 提交于 2019-11-27 04:05:50
问题 I have two collections User { "_id" : ObjectId("584aac38686860d502929b8b"), "name" : "John" } Role { "_id" : ObjectId("584aaca6686860d502929b8d"), "role" : "Admin", "userId" : "584aac38686860d502929b8b" } I want to join these collection based on the userId (in role collection) - _id ( in user collection). I tried the below query: db.role.aggregate( { $lookup: { from: 'user', localField: 'userId', foreignField: '_id', as: 'output' } } ); This gives me expected results as long as i store userId

How to convert string to objectId in LocalField for $lookup Mongodb [duplicate]

由 橙三吉。 提交于 2019-11-27 03:51:30
问题 This question already has an answer here : Matching ObjectId to String for $graphLookup (1 answer) Closed last year . I want to add join collections using $lookup in mongodb. I am trying as below { $lookup:{ from:"User", localField:"assignedId", foreignField:"_id", as:"dataa"} } Now I have two collections User contains objectid of users like "_id" : ObjectId("56ab6663d69d2d1100c074db"), and Tasks where it contains assignedId as a string "assignedId":"56ab6663d69d2d1100c074db" Now, when

Algorithm/steps to find Longest Prefix search in Patricia Trie

由 给你一囗甜甜゛ 提交于 2019-11-27 03:33:54
问题 I am implementing Patricia tries for IP prefix lookup, I could get the code working for complete key match, but facing problems with prefix search, when there are keys which are prefixes of other keys, like: 1.2.3.0 1.2.0.0 Can anyone help me with the algorithm for prefix searches in the above case Should I consider these as keys of separate length (i.e, /24 and 16) ? 回答1: Take a look at Net-Patricia. This is an implementation of a Patricia trie to look up IP addresses. The interface is perl,
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