Search Results

Search found 3047 results on 122 pages for 'subset sum'.

Page 97/122 | < Previous Page | 93 94 95 96 97 98 99 100 101 102 103 104  | Next Page >

  • MySQL GIS and Spatial Extensions - how to map regions and query against them

    - by chibineku
    I am trying to make a smartphone app which will return a list of users within a certain proximity, say 100m. It's easy to get the coordinates of my BlackBerry and write them to a database, but in order to return a list of other users within 100m, I need to pull every other record from the database and compare the distance between the two points, checking to see if it's within range, before outputting that user's information. This is going to be time consuming if there are many users involved. So I would like to map areas (countries, cities, I'm not yet sure of the resolution I'll need) so that I can first target a smaller subset of all users. This will save on processing time. I have read the basics of GIS and spatial querying on the mysql website but to be honest the query is over my head and I hate copying and pasting code without understanding it. Plus it only checks for proximity - I want to first check if a coordinate falls within a certain area. Does anyone have any experience of such matters and feel like giving me some pointers? Resources such as any preexisting databases of points describing countries as polygons would be really helpful too. Many thanks to anyone who takes the time :)

    Read the article

  • What is a data structure for quickly finding non-empty intersections of a list of sets?

    - by Andrey Fedorov
    I have a set of N items, which are sets of integers, let's assume it's ordered and call it I[1..N]. Given a candidate set, I need to find the subset of I which have non-empty intersections with the candidate. So, for example, if: I = [{1,2}, {2,3}, {4,5}] I'm looking to define valid_items(items, candidate), such that: valid_items(I, {1}) == {1} valid_items(I, {2}) == {1, 2} valid_items(I, {3,4}) == {2, 3} I'm trying to optimize for one given set I and a variable candidate sets. Currently I am doing this by caching items_containing[n] = {the sets which contain n}. In the above example, that would be: items_containing = [{}, {1}, {1,2}, {2}, {3}, {3}] That is, 0 is contained in no items, 1 is contained in item 1, 2 is contained in itmes 1 and 2, 2 is contained in item 2, 3 is contained in item 2, and 4 and 5 are contained in item 3. That way, I can define valid_items(I, candidate) = union(items_containing[n] for n in candidate). Is there any more efficient data structure (of a reasonable size) for caching the result of this union? The obvious example of space 2^N is not acceptable, but N or N*log(N) would be.

    Read the article

  • oracle query with inconsistent results

    - by Spencer Stejskal
    Im having a very strange problem, i have a complicated view that returns incorrect data when i query on a particular column. heres an example: select empname, has_garnishment from timecard_v2 where empname = 'Testerson, Testy'; this returns the single result 'Testerson, Testy', 'N' however, if i use the query: select empname, has_garnishment from timecard_v2 where empname = 'Testerson, Testy' and has_garnishment = 'Y'; this returns the single result 'Testerson, Testy', 'Y' The second query should return a subset of the first query, but it returns a different answer. I have dissected the view and determined that this section of the view definition is where the problem arises(Note, I removed all of the select clause except the parts of interests for clarity, in the full query all joined tables are required): SELECT e.fullname empname , NVL2(ded.has_garn, 'Y', 'N') has_garnishment FROM timecard tc , orderdetail od , orderassign oa , employee e , employee3 e3 , customer10 c10 , order_misc om, (SELECT COUNT(*) has_garn, v_ssn FROM deductions WHERE yymmdd_stop = 0 OR (LENGTH(yymmdd_stop) = 7 AND to_date(SUBSTR(yymmdd_stop, 2), 'YYMMDD') sysdate) GROUP BY v_ssn ) ded WHERE oa.lrn(+) = tc.lrn_order AND om.lrn(+) = od.lrn AND od.orderno = oa.orderno AND e.ssn = tc.ssn AND c10.custno = tc.custno AND e.lrn = e3.lrn AND e.ssn = ded.v_ssn(+) One thing of note about the definition of the 'ded' subquery. The v_ssn field is a virtual field on the deductions table. I am not a DBA im a software developer but we recently lost our DBA and the new one is still getting up to speed so im trying to debug this issue. That being said, please explain things a little more thoroughly then you would for a fellow oracle expert. thanks

    Read the article

  • Odd behavior when recursively building a return type for variadic functions

    - by Dennis Zickefoose
    This is probably going to be a really simple explanation, but I'm going to give as much backstory as possible in case I'm wrong. Advanced apologies for being so verbose. I'm using gcc4.5, and I realize the c++0x support is still somewhat experimental, but I'm going to act on the assumption that there's a non-bug related reason for the behavior I'm seeing. I'm experimenting with variadic function templates. The end goal was to build a cons-list out of std::pair. It wasn't meant to be a custom type, just a string of pair objects. The function that constructs the list would have to be in some way recursive, with the ultimate return value being dependent on the result of the recursive calls. As an added twist, successive parameters are added together before being inserted into the list. So if I pass [1, 2, 3, 4, 5, 6] the end result should be {1+2, {3+4, 5+6}}. My initial attempt was fairly naive. A function, Build, with two overloads. One took two identical parameters and simply returned their sum. The other took two parameters and a parameter pack. The return value was a pair consisting of the sum of the two set parameters, and the recursive call. In retrospect, this was obviously a flawed strategy, because the function isn't declared when I try to figure out its return type, so it has no choice but to resolve to the non-recursive version. That I understand. Where I got confused was the second iteration. I decided to make those functions static members of a template class. The function calls themselves are not parameterized, but instead the entire class is. My assumption was that when the recursive function attempts to generate its return type, it would instantiate a whole new version of the structure with its own static function, and everything would work itself out. The result was: "error: no matching function for call to BuildStruct<double, double, char, char>::Go(const char&, const char&)" The offending code: static auto Go(const Type& t0, const Type& t1, const Types&... rest) -> std::pair<Type, decltype(BuildStruct<Types...>::Go(rest...))> My confusion comes from the fact that the parameters to BuildStruct should always be the same types as the arguments sent to BuildStruct::Go, but in the error code Go is missing the initial two double parameters. What am I missing here? If my initial assumption about how the static functions would be chosen was incorrect, why is it trying to call the wrong function rather than just not finding a function at all? It seems to just be mixing types willy-nilly, and I just can't come up with an explanation as to why. If I add additional parameters to the initial call, it always burrows down to that last step before failing, so presumably the recursion itself is at least partially working. This is in direct contrast to the initial attempt, which always failed to find a function call right away. Ultimately, I've gotten past the problem, with a fairly elegant solution that hardly resembles either of the first two attempts. So I know how to do what I want to do. I'm looking for an explanation for the failure I saw. Full code to follow since I'm sure my verbal description was insufficient. First some boilerplate, if you feel compelled to execute the code and see it for yourself. Then the initial attempt, which failed reasonably, then the second attempt, which did not. #include <iostream> using std::cout; using std::endl; #include <utility> template<typename T1, typename T2> std::ostream& operator <<(std::ostream& str, const std::pair<T1, T2>& p) { return str << "[" << p.first << ", " << p.second << "]"; } //Insert code here int main() { Execute(5, 6, 4.3, 2.2, 'c', 'd'); Execute(5, 6, 4.3, 2.2); Execute(5, 6); return 0; } Non-struct solution: template<typename Type> Type BuildFunction(const Type& t0, const Type& t1) { return t0 + t1; } template<typename Type, typename... Rest> auto BuildFunction(const Type& t0, const Type& t1, const Rest&... rest) -> std::pair<Type, decltype(BuildFunction(rest...))> { return std::pair<Type, decltype(BuildFunction(rest...))> (t0 + t1, BuildFunction(rest...)); } template<typename... Types> void Execute(const Types&... t) { cout << BuildFunction(t...) << endl; } Resulting errors: test.cpp: In function 'void Execute(const Types& ...) [with Types = {int, int, double, double, char, char}]': test.cpp:33:35: instantiated from here test.cpp:28:3: error: no matching function for call to 'BuildFunction(const int&, const int&, const double&, const double&, const char&, const char&)' Struct solution: template<typename... Types> struct BuildStruct; template<typename Type> struct BuildStruct<Type, Type> { static Type Go(const Type& t0, const Type& t1) { return t0 + t1; } }; template<typename Type, typename... Types> struct BuildStruct<Type, Type, Types...> { static auto Go(const Type& t0, const Type& t1, const Types&... rest) -> std::pair<Type, decltype(BuildStruct<Types...>::Go(rest...))> { return std::pair<Type, decltype(BuildStruct<Types...>::Go(rest...))> (t0 + t1, BuildStruct<Types...>::Go(rest...)); } }; template<typename... Types> void Execute(const Types&... t) { cout << BuildStruct<Types...>::Go(t...) << endl; } Resulting errors: test.cpp: In instantiation of 'BuildStruct<int, int, double, double, char, char>': test.cpp:33:3: instantiated from 'void Execute(const Types& ...) [with Types = {int, int, double, double, char, char}]' test.cpp:38:41: instantiated from here test.cpp:24:15: error: no matching function for call to 'BuildStruct<double, double, char, char>::Go(const char&, const char&)' test.cpp:24:15: note: candidate is: static std::pair<Type, decltype (BuildStruct<Types ...>::Go(BuildStruct<Type, Type, Types ...>::Go::rest ...))> BuildStruct<Type, Type, Types ...>::Go(const Type&, const Type&, const Types& ...) [with Type = double, Types = {char, char}, decltype (BuildStruct<Types ...>::Go(BuildStruct<Type, Type, Types ...>::Go::rest ...)) = char] test.cpp: In function 'void Execute(const Types& ...) [with Types = {int, int, double, double, char, char}]': test.cpp:38:41: instantiated from here test.cpp:33:3: error: 'Go' is not a member of 'BuildStruct<int, int, double, double, char, char>'

    Read the article

  • What's the standard convention for creating a new NSArray from an existing NSArray?

    - by Prairiedogg
    Let's say I have an NSArray of NSDictionaries that is 10 elements long. I want to create a second NSArray with the values for a single key on each dictionary. The best way I can figure to do this is: NSMutableArray *nameArray = [[NSMutableArray alloc] initWithCapacity:[array count]]; for (NSDictionary *p in array) { [nameArray addObject:[p objectForKey:@"name"]]; } self.my_new_array = array; [array release]; [nameArray release]; } But in theory, I should be able to get away with not using a mutable array and using a counter in conjunction with [nameArray addObjectAtIndex:count], because the new list should be exactly as long as the old list. Please note that I am NOT trying to filter for a subset of the original array, but make a new array with exactly the same number of elements, just with values dredged up from the some arbitrary attribute of each element in the array. In python one could solve this problem like this: new_list = [p['name'] for p in old_list] or if you were a masochist, like this: new_list = map(lambda p: p['name'], old_list) Having to be slightly more explicit in objective-c makes me wonder if there is an accepted common way of handling these situations.

    Read the article

  • Method of transforming 3D vectors with a matrix

    - by Drew Noakes
    I've been doing some reading on transforming Vector3 with matrices, and am tossing up digging deeper into the math and coding this myself versus using existing code. For whatever reason my school curriculum never included matrices, so I'm filling a gap in my knowledge. Thankfully I only need a few simple things, I think. Context is that I'm programming a robot for the RoboCup 3D league. I'm coding it in C# but it'll have to run on Mono. Ideally I wouldn't use any existing graphics libraries for this (WinForms/WPF/XNA) as all I really need is a neat subset of matrix transformations. Specifically, I need translation and x/y/z rotations, and a way of combining multiple transformations into a single matrix. This will then be applied to my own Vector3 type to produce the transformed Vector3. I've read different advice about this. For example, some model the transformation with a 4x3 matrix, others with a 4x4 matrix. Also, some examples show that you need a forth value for the vector's matrix of 1. What happens to this value when it's included in the output? [1 0 0 0] [x y z 1] * [0 1 0 0] = [a b c d] [0 0 1 0] [2 4 6 1] The parts I'm missing are: What sizes my matrices should be Compositing transformations by multiplying the transformation matrices together Transforming 3D vectors with the resulting matrix As I mostly just want to get this running, any psuedo-code would be great. Information about what matrix values perform what transformations is quite clearly defined on many pages, so need not be discussed here unless you're very keen :)

    Read the article

  • Database design and foreign keys: Where should they be added in related tables?

    - by Carvell Fenton
    I have a relatively simple subset of tables in my database for tracking something called sessions. These are academic sessions (think offerings of a particular program). The tables to represent a sessions information are: sessions session_terms session_subjects session_mark_item_info session_marks All of these tables have their own primary keys, and are like a tree, in that sessions have terms, terms have subjects, subjects have mark items, etc. So each on would have at least its "parent's" foreign key. My question is, design wise is it a good idea to include the sessions primary key in the other tables as a foreign key to easily select related session items, or is that too much redundency? If I include the session foreign key (or all parent foreign keys from tables up the heirarchy) in all the tables, I can easily select all the marks for a session. As an example, something like SELECT mark FROM session_marks WHERE sessionID=... If I don't, then I would have to combine selects with something like WHERE something IN (SELECT... Which approach is "more correct" or efficient? Thanks in advance!

    Read the article

  • Idiomatic way to build a custom structure from XML zipper in Clojure

    - by Checkers
    Say, I'm parsing an RSS feed and want to extract a subset of information from it. (def feed (-> "http://..." clojure.zip/xml-zip clojure.xml/parse)) I can get links and titles separately: (xml-> feed :channel :item :link text) (xml-> feed :channel :item :title text) However I can't figure out the way to extract them at the same time without traversing the zipper more than once, e.g. (let [feed (-> "http://..." clojure.zip/xml-zip clojure.xml/parse)] (zipmap (xml-> feed :channel :item :link text) (xml-> feed :channel :item :title text))) ...or a variation of thereof, involving mapping multiple sequences to a function that incrementally builds a map with, say, assoc. Not only I have to traverse the sequence multiple times, the sequences also have separate states, so elements must be "aligned", so to speak. That is, in a more complex case than RSS, a sub-element may be missing in particular element, making one of sequences shorter by one (there are no gaps). So the result may actually be incorrect. Is there a better way or is it, in fact, the way you do it in Clojure?

    Read the article

  • Project euler problem 45

    - by Peter
    Hi, I'm not yet a skilled programmer but I thought this was an interesting problem and I thought I'd give it a go. Triangle, pentagonal, and hexagonal numbers are generated by the following formulae: Triangle T_(n)=n(n+1)/2 1, 3, 6, 10, 15, ... Pentagonal P_(n)=n(3n-1)/2 1, 5, 12, 22, 35, ... Hexagonal H_(n)=n(2n-1) 1, 6, 15, 28, 45, ... It can be verified that T_(285) = P_(165) = H_(143) = 40755. Find the next triangle number that is also pentagonal and hexagonal. Is the task description. I know that Hexagonal numbers are a subset of triangle numbers which means that you only have to find a number where Hn=Pn. But I can't seem to get my code to work. I only know java language which is why I'm having trouble finding a solution on the net womewhere. Anyway hope someone can help. Here's my code public class NextNumber { public NextNumber() { next(); } public void next() { int n = 144; int i = 165; int p = i * (3 * i - 1) / 2; int h = n * (2 * n - 1); while(p!=h) { n++; h = n * (2 * n - 1); if (h == p) { System.out.println("the next triangular number is" + h); } else { while (h > p) { i++; p = i * (3 * i - 1) / 2; } if (h == p) { System.out.println("the next triangular number is" + h); break; } else if (p > h) { System.out.println("bummer"); } } } } } I realize it's probably a very slow and ineffecient code but that doesn't concern me much at this point I only care about finding the next number even if it would take my computer years :) . Peter

    Read the article

  • De-normalization alternative to specific MYSQL problem?

    - by Booker
    I am facing quite a specific optimization problem. I currently have 4 normalized tables of data. Every second, possibly thousands of users will pull down up-to-date info from these tables using AJAX. The thing is that I can predict relatively easily which subset of data they need... The most recent 100 or so entries in those 4 normalized tables. I have been researching de-normalization... but feel that perhaps there is an easier solution. I was thinking that I could somehow every second run one sql query to condense the needed info, store it in a temp cached table and then have all of the user queries just draw from this. This will allow the complex join of 4 tables to only be run once, and then from there the users just need to do a simple lookup from the cached table. I really don't know if this is feasible. Comments on this or any other suggestions would be much appreciated. Thanks!

    Read the article

  • Finding Common Byte Sequences in MS SQL TEXT Column

    - by regex
    Hello All, Short Desc: I'm curious to see if I can use SQL Analysis services or some other MS SQL service to mine some data for me that will show commonalities between SQL TEXT fields in a dataset. Long Desc I am looking at a subset of data that consists of about 10,000 rows of TEXT blobs which are used as a notes column in a issue tracking (ticketing) software. I would like to use something out of the box (without having to build something) that might be able to parse through all of the rows and find commonly used byte sequences in the "Notes" column. In other words, I want to find commonly used phrases (two to three word phrases, so 9 - 20 character sections of the TEXT blob). This will help me better determine if associate's notes contain similar phrases (troubleshooting techniques) that we could standardize in our troubleshooting process flow. Closing Note I'd really rather not build an application to do this as my method will probably not be the most efficient way to do it. Hopefully all this makes sense. Please let me know in the comments if anything needs clarification. Thanks in advance for your help.

    Read the article

  • "Order By" in LINQ-to-SQL Causes performance issues

    - by panamack
    I've set out to write a method in my C# application which can return an ordered subset of names from a table containing about 2000 names starting at the 100th name and returning the next 20 names. I'm doing this so I can populate a WPF DataGrid in my UI and do some custom paging. I've been using LINQ to SQL but hit a snag with this long executing query so I'm examining the SQL the LINQ query is using (Query B below). Query A runs well: SELECT TOP (20) [t0].[subject_id] AS [Subject_id], [t0].[session_id] AS [Session_id], [t0].[name] AS [Name] FROM [Subjects] AS [t0] WHERE (NOT (EXISTS( SELECT NULL AS [EMPTY] FROM ( SELECT TOP (100) [t1].[subject_id] FROM [Subjects] AS [t1] WHERE [t1].[session_id] = 1 ORDER BY [t1].[name] ) AS [t2] WHERE [t0].[subject_id] = [t2].[subject_id] ))) AND ([t0].[session_id] = 1) Query B takes 40 seconds: SELECT TOP (20) [t0].[subject_id] AS [Subject_id], [t0].[session_id] AS [Session_id], [t0].[name] AS [Name] FROM [Subjects] AS [t0] WHERE (NOT (EXISTS( SELECT NULL AS [EMPTY] FROM ( SELECT TOP (100) [t1].[subject_id] FROM [Subjects] AS [t1] WHERE [t1].[session_id] = 1 ORDER BY [t1].[name] ) AS [t2] WHERE [t0].[subject_id] = [t2].[subject_id] ))) AND ([t0].[session_id] = 1) ORDER BY [t0].[name] When I add the ORDER BY [t0].[name] to the outer query it slows down the query. How can I improve the second query? This was my LINQ stuff Nick int sessionId = 1; int start = 100; int count = 20; // Query subjects with the shoot's session id var subjects = cldb.Subjects.Where<Subject>(s => s.Session_id == sessionId); // Filter as per params var orderedSubjects = subjects .OrderBy<Subject, string>( s => s.Col_zero ); var filteredSubjects = orderedSubjects .Skip<Subject>(start) .Take<Subject>(count);

    Read the article

  • Delphi: Problems with TList of Frames

    - by Dan Kelly
    I'm having a problem with an interface that consists of a number of frames (normally 25) within a TScrollBox. There are 2 problems, and I am hoping that one is a consequence of the other... Background: When the application starts up, I create 25 frames, each containing approx. 20 controls, which are then populated with the default information. The user can then click on a control to limit the search to a subset of information at which point I free and recreate my frames (as the search may return < 25 records) The problem: If I quit the application after the initial search then it takes approx. 5 seconds to return to Delphi. After the 2nd search (and dispose / recreate of frames) it takes approx. 20 seconds) Whilst I could rewrite the application to only create the frames once, I would like to understand what is going on. Here is my create routine: procedure TMF.CreateFrame(i: Integer; var FrameBottom: Integer); var NewFrame: TSF; begin NewFrame := TSF.Create(Self); NewFrame.Name := 'SF' + IntToStr(i); if i = 0 then NewSF.Top := 8 else NewSF.Top := FrameBottom + 8; FrameBottom := NewFrame.Top + NewFrame.Height; NewFrame.Parent := ScrollBox1; FrameList.Add(NewFrame); end; And here is my delete routine: procedure TMF.ClearFrames; var i: Integer; SF: TSF; begin for i := 0 to MF.FrameList.Count -1 do begin SF := FrameList[i]; SF.Free; end; FrameList.Clear; end; What am I missing?

    Read the article

  • Google Analytics - Goals - Advanced Segments - Does it keep cookies for tracking visitors?

    - by Kuko
    Hi there, I am working with Google Analytics - Goals and Funnels for quite sometime, but one thing is is not clear for me. I would very much appreciate if you could help me. We are advertising on several sites rotating several different ads. Our main goal is to collect as many sign-ups (new users) as possible for as low price as possible. We use to advertise the way, that each ad has the same URL where to land, but contains different parameter (e.g. http://www.brautpunkt.de/?ref=fb01 or ..... .de/?ref=adw03). My question is: If I am looking at the goals (Goals Overview), filtering it through Advanced Segments (Landing Page contains /?ref=fb01) is this subset of goals done only by the users who registered in the same session after they came on our site directly from the ad? or also by those users who came first time through this ad (/?ref=fb01), didn't register in the same session but came directly for example on the other day and register than? Thank you very much in advance for your advice. Peter

    Read the article

  • R - removing rows and replacing values using conditions from multiple columns

    - by lecodesportif
    I want to filter out all values of var3 < 5 while keeping at least one occurrence of each value of var1. > foo <- data.frame(var1= c(1, 1, 2, 3, 3, 4, 4, 5), var2=c(9, 5, 13, 9, 12, 11, 13, 9), var3=c(6, 8, 3, 6, 4, 7, 2, 9)) > foo var1 var2 var3 1 1 9 6 2 1 5 8 3 2 13 3 4 3 9 6 5 3 12 4 6 4 11 7 7 4 13 2 8 5 9 9 subset(foo, (foo$var3>=5)) would remove row 3, 5 and 7 and I would have lost var1==2. I want to remove the row if there is another value of var1 that fulfills the condition foo$var3 = 5. See row 5. I want to keep the row, assiging NA to var2 and var3 if all occurrences of a value var1 do not fulfill the condition foo$var3 = 5. This is the result I expect: var1 var2 var3 1 1 9 6 2 1 5 8 3 2 NA NA 4 3 9 6 6 4 11 7 8 5 9 9 This is the closest I got: > foo$var3[ foo$var3 < 5 ] = NA > foo$var2[ is.na(foo$var3) ] = NA > foo var1 var2 var3 1 1 9 6 2 1 5 8 3 2 NA NA 4 3 9 6 5 3 NA NA 6 4 11 7 7 4 NA NA 8 5 9 9 So I guess I just need to know how to conditionally remove the row.

    Read the article

  • Web-app currency input/manipulation/calculation with javascript .. there has got to be a better (fra

    - by dreftymac
    BACKGROUND: I am of the "user-input-lockdown" school of thought. Whenever possible, I try to mistrust and sanitize user input, both client side and server side; and I try to take multiple opportunities to restrict possible inputs to a known subset of possibilities, usually this means providing a lot of checkboxes and select lists. (This is from the usability side of things, I know security-wise that malicious users can easily bypass fixed user input GUI controls). PROBLEM: Anyway, the problem always arises with non-fixed input of currency. Whenever I have to accept a freely-specified dollar amount as user input, I always have to confront these problems/annoyances and it is always painful: 1) Make sure to give the user two input boxes for each currency_datapoint, one for the whole_dollar_part and another for the fractional_pennies_part 2) Whenever the user changes a currency_datapoint, provide keystroke-by-keystroke GUI feedback to let them know whether the currency_datapoint is well-formed, with context-appropriate validation rules (e.g., no negatives?, nonzero only?, numeric only!, no non-numeric punctuation! no symbols!) 3) For display purposes, every user-provided currency_datapoint should be translated to human-readable currency formatting (dollar sign, period, commas provided by the app, where appropriate) 4) For calculation purposes, every user-provided currency_datapoint has to be converted to integer (all pennies, to avoid floating point errors) and summed into a grand total with zero or more subtotals. 5) Every user-provided currency_datapoint should be displayed or displayable in a nice "tabular" format, which auto-updates as the user enters each currency_datapoint, including a baloon that warns when one or more currency_datapoints is not well-formed. I seem to be re-inventing this wheel every time I have to work with currency in Javascript on the client side (server side is a bit more flexible since most programming languages have higher-level currency formatting logic). QUESTION: Has anyone out there solved the problem of dealing with the above issues, client side, in a way that is server-side-technology-stack agnostic, (preferrably plain javascript or jquery)? This is getting old, there has to be a better way.

    Read the article

  • Python - Checking for membership inside nested dict

    - by victorhooi
    heya, This is a followup questions to this one: http://stackoverflow.com/questions/2901422/python-dictreader-skipping-rows-with-missing-columns Turns out I was being silly, and using the wrong ID field. I'm using Python 3.x here. I have a dict of employees, indexed by a string, "directory_id". Each value is a nested dict with employee attributes (phone number, surname etc.). One of these values is a secondary ID, say "internal_id", and another is their manager, call it "manager_internal_id". The "internal_id" field is non-mandatory, and not every employee has one. (I've simplified the fields a little, both to make it easier to read, and also for privacy/compliance reasons). The issue here is that we index (key) each employee by their directory_id, but when we lookup their manager, we need to find managers by their "internal_id". Before, when employee.keys() was a list of internal_ids, I was using a membership check on this. Now, the last part of my if statement won't work, since the internal_ids is part of the dict values, instead of the key itself. def lookup_supervisor(manager_internal_id, employees): if manager_internal_idis not None and manager_internal_id!= "" and manager_internal_id in employees.keys(): return (employees[manager_internal_id]['mail'], employees[manager_internal_id]['givenName'], employees[manager_internal_id]['sn']) else: return ('Supervisor Not Found', 'Supervisor Not Found', 'Supervisor Not Found') So the first question is, how do I check whether the manager_internal_id is present in the dict's values. I've tried substituting employee.keys() with employee.values(), that didn't work. Also, I'm hoping for something a little more efficient, not sure if there's a way to get a subset of the values, specifically, all the entries for employees[directory_id]['internal_id']. Hopefully there's some Pythonic way of doing this, without using a massive heap of nested for/if loops. My second question is, how do I then cleanly return the required employee attributes (mail, givenname, surname etc.). My for loop is iterating over each employee, and calling lookup_supervisor. I'm feeling a bit stupid/stumped here. def tidy_data(employees): for directory_id, data in employees.items(): # We really shouldnt' be passing employees back and forth like this - hmm, classes? data['SupervisorEmail'], data['SupervisorFirstName'], data['SupervisorSurname'] = lookup_supervisor(data['manager_internal_id'], employees) Thanks in advance =), Victor

    Read the article

  • Help with jQuery Validation plugin and a form that uses 'panels'

    - by alex
    I have a form that works in 'sections' that I will refer to as 'panels'. By default, the form is listed out on the page, one panel after the other. However, with JavaScript, it puts the panels into one panel viewer, and displays them one after the other (with prev/next buttons). Example Form Workflow Panel 1: User Details - Panel 2: User Location - Panel 3: User Info - Panel 4: Confirm Details I am using the jQuery Validation plugin. My problem is, I have set up all the rules for all the inputs in the first 3 panels, and I'd like to be able to only validate a subset of them per panel. Example, when pushing 'next panel' after completing name & email (in the 1st, user details panel), I'd like to do a validation only on that panel first, and then get a boolean response (if the 1st panel validated), and if true, then proceed to the next panel. I've played around with a bit of the config, but unfortunately could not get it to work as I wanted. This is my first project with this plugin so I'm quite new to it! Is there a way to add rules dynamically to the plugin? i.e. not on $('form').validate(options) ? What I'd like to do, is call the validate() on the form, with all the error messages, and then on the 'next panel' code, do a switch case to determine which rules to add, and then call a validate() myself.

    Read the article

  • Commercial web application--scalable database design

    - by Rob Campbell
    I'm designing a set of web apps to track scientific laboratory data. Each laboratory has several members, each of whom will access both their own data and that of their laboratory as a whole. Many typical queries will thus be expected to return records of multiple members (e.g. my mouse, joe's mouse and sally's mouse). I think I have the database fairly well normalized. I'm now wondering how to ensure that users can efficiently access both their own data and their lab's data set when it is mixed among (hopefully) a whole ton of records from other labs. What I've come up with so far is that most tables will end with two fields: user_id and labgroup_id. The WHERE clause of any SELECT statement will include the appropriate reference to one of the id fields ("...WHERE 'labroup_id=n..." or "...WHERE user_id=n..."). My questions are: Is this an approach that will scale to 10^6 or more records? If so, what's the best way to use these fields in a query so that it most efficiently searches the relevant subset of the database? e.g. Should the first step in querying be to create a temporary table containing just the labgroup's data? Or will indexing using some combination of the id, user_id, and labroup_id fields be sufficient at that scale? I thank any responders very much in advance.

    Read the article

  • How to get more detail from an exception?

    - by cusimar9
    I have a .NET 4.0 web application which implements an error handler within the Application_Error event of Global.asax. When an exception occurs this intercepts it and sends me an email including a variety of information like the logged in user, the page the error occurred on, the contents of the session etc. This is all great but there is some fundamental detail missing which I seem unable to locate. For instance, this is a subset of an error I would receive and the associated stack trace: Source: Telerik.Web.UI Message: Selection out of range Parameter name: value Stack trace: at Telerik.Web.UI.RadComboBox.PerformDataBinding(IEnumerable dataSource) at Telerik.Web.UI.RadComboBox.OnDataSourceViewSelectCallback(IEnumerable data) at System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) at Telerik.Web.UI.RadComboBox.OnDataBinding(EventArgs e) at Telerik.Web.UI.RadComboBox.PerformSelect() at System.Web.UI.WebControls.BaseDataBoundControl.DataBind() at Telerik.Web.UI.RadComboBox.DataBind() at System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound() at Telerik.Web.UI.RadComboBox.OnPreRender(EventArgs e) at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) Now as lovely as this is I could do with knowing a) the name of the control and b) the value which caused the control to be 'out of range'. Any suggestions about how I could get this sort of information? I've run this in debug mode and the objects passed to Global.asax don't seem to hold any more detail that I can see.

    Read the article

  • How do I do MongoDB console-style queries in PHP?

    - by Zoe Boles
    I'm trying to get a MongoDB query from the javascript console into my PHP app. What I'm trying to avoid is having to translate the query into the PHP "native driver"'s format... I don't want to hand build arrays and hand-chain functions any more than I want to manually build an array of MySQL's internal query structure just to get data. I already have a string producing the exact content I want in the Mongo console: db.intake.find({"processed": {"$exists": "false"}}).sort({"insert_date": "1"}).limit(10); The question is, is there a way for me to hand this string, as is, to MongoDB and have it return a cursor with the dataset I request? Right now I'm at the "write your own parser because it's not valid json to kinda turn a subset of valid Mongo queries into the format the PHP native driver wants" state, which isn't very fun. I don't want an ORM or a massive wrapper library; I just want to give a function my query string as it exists in the console and get an Iterator back that I can work with. I know there are a couple of PHP-based Mongo manager applications that apparently take console-style queries and handle them, but initial browsing through their code, I'm not sure how they handle the translation. I absolutely love working with mongo in the console, but I'm rapidly starting to loathe the thought of converting every query into the format the native writer wants...

    Read the article

  • What is the best way to store site configuration data?

    - by DaveDev
    I have a question about storing site configuration data. We have a platform for web applications. The idea is that different clients can have their data hosted and displayed on their own site which sits on top of this platform. Each site has a configuration which determines which panels relevant to the client appear on which pages. The system was originally designed to keep all the configuration data for each site in a database. When the site is loaded all the configuration data is loaded into a SiteConfiguration object, and the clients panels are generated based on the content of this object. This works, but I find it very difficult to work with to apply change requests or add new sites because there is so much data to sift through and it's difficult maintain a mental model of the site and its configuration. Recently I've been tasked with developing a subset of some of the sites to be generated as PDF documents for printing. I decided to take a different approach to how I would define the configuration in that instead of storing configuration data in the database, I wrote XML files to contain the data. I find it much easier to work with because instead of reading meaningless rows of data which are related to other meaningless rows of data, I have meaningful documents with semantic, readable information with the relationships defined by visually understandable element nesting. So now with these 2 approaches to storing site configuration data, I'd like to get the opinions of people more experienced in dealing with this issue on dealing with these two approaches. What is the best way of storing site configuration data? Is there a better way than the two ways I outlined here? note: StackOverflow is telling me the question appears to be subjective and is likely to be closed. I'm not trying to be subjective. I'd like to know how best to approach this issue next time and if people with industry experience on this could provide some input.

    Read the article

  • Database schemas WAY out of sync - need to get up to date without losing data

    - by Zind
    The problem: we have one application that has a portion which is used by a very small subset of the total users, and that part of the application is running off of a separate database as well. In a perfect world, the schemas of the two databases would be synced up, but such is not the case. Some migrations have been run on the smaller database, most haven't; and furthermore, there is nothing such as revision number to be able to easily identify which have and which haven't. We would like to solve this quandary for future projects. During a discussion we've come up with the following possible plan of action, and I am wondering if anyone knows of any project which has already solved this problem: What we would like to do is create an empty database from the schema of the large fully-migrated database, and then move all of the data from the smaller non-migrated database into that empty one. If it makes things easier, it can probably be assumed for the sake of this problem specifically that no migrations have ever removed anything, only added. Else, if there are other known solutions, I'd like to hear them as well.

    Read the article

  • Parse multiple named command line parameters

    - by scholzr
    I need to add the ability to a program to accept multiple named parameters when opening the program via the command line. i.e. program.exe /param1=value /param2=value and then be able to utilize these parameters as variables in the program. I have found a couple of ways to accomplish pieces of this, but can't seem to figure out how to put it all together. I have been able to pass one named parameter and recover it using the code below, and while I could duplicate it for every possible named parameter, I know that can't be the preffered way to do this. Dim inputArgument As String = "/input=" Dim inputName As String = "" For Each s As String In My.Application.CommandLineArgs If s.ToLower.StartsWith(inputArgument) Then inputName = s.Remove(0, inputArgument.Length) End If Next Alternatively, I can get multiple unnamed parameters from the command line using My.Application.CommandLineArgs But this requires that the parameters all be passed in the same order/format each time. I need to be able to pass a random subset of parameters each time. Ultimately, what I would like to be able to do, is separate each argument and value, and load it into a multidimentional array for later use. I know that I could find a way to do this by separating the string at the "=" and stripping the "/", but as I am somewhat new to this, I wanted to see if there was a "preffered" way for dealing with multiple named parameters?

    Read the article

  • EF/LINQ: Where() against a property of a subtype

    - by ladenedge
    I have a set of POCOs, all of which implement the following simple interface: interface IIdObject { int Id { get; set; } } A subset of these POCOs implement this additional interface: interface IDeletableObject : IIdObject { bool IsDeleted { get; set; } } I have a repository hierarchy that looks something like this: IRepository<T <: BasicRepository<T <: ValidatingRepository<T (where T is IIdObject) I'm trying to add a FilteringRepository to the hierarchy such that all of the POCOs that implement IDeletableObject have a Where(p => p.IsDeleted == false) filter applied before any other queries take place. My goal is to avoid duplicating the hierarchy solely for IDeletableObjects. My first attempt looked like this: public override IQueryable<T> Query() { return base.Query().Where(t => ((IDeletableObject)t).IsDeleted == false); } This works well with LINQ to Objects, but when I switch to an EF backend I get: "LINQ to Entities only supports casting Entity Data Model primitive types." I went on to try some fancier parameterized solutions, but they ultimately failed because I couldn't make T covariant in the following case for some reason I don't quite understand: interface IQueryFilter<out T> // error { Expression<Func<T, bool>> GetFilter(); } I'd be happy to go into more detail on my more complicated solutions if it would help, but I think I'll stop here for now in hope that someone might have an idea for me to try. Thanks very much in advance!

    Read the article

< Previous Page | 93 94 95 96 97 98 99 100 101 102 103 104  | Next Page >