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• probability of subset sum after rolling dice 4 times

  - by binger

  If we roll 4 dices (fair), what is the probability of "sum of subset" being 5. e.g. 1432,1121, 2344, 2354 have a subset sum of 5. Can you illustrate how to calculate this.

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• c source code to remove subset transactions form text file

  - by user324887

  I have a file containing data as follows 10 20 30 40 70 20 30 70 30 40 10 20 29 70 80 90 20 30 40 40 45 65 10 20 80 45 65 20 I want to remove all subset transaction from this file. output file should be like follows 10 20 30 40 70 29 70 80 90 20 30 40 40 45 65 10 20 80 Where records like 20 30 70 30 40 10 20 45 65 20 are removed because of they are subset of other records.

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• c source code to remove subset transactions from text file

  - by user324887

  I have a file containing data as follows 10 20 30 40 70 20 30 70 30 40 10 20 29 70 80 90 20 30 40 40 45 65 10 20 80 45 65 20 I want to remove all subset transaction from this file. output file should be like follows 10 20 30 40 70 29 70 80 90 20 30 40 40 45 65 10 20 80 Where records like 20 30 70 30 40 10 20 45 65 20 are removed because of they are subset of other records.

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• removing subset transactions form file

  - by user324887

  I have a file containing data as follows 10 20 30 40 70 20 30 70 30 40 10 20 29 70 80 90 20 30 40 40 45 65 10 20 80 45 65 20 I want to remove all subset transaction from this file. output file should be like follows 10 20 30 40 70 29 70 80 90 20 30 40 40 45 65 10 20 80 Where records like 20 30 70 30 40 10 20 45 65 20 are removed because of they are subset of other records.

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• Five unique, random numbers from a subset

  - by tau

  I know similar questions come up a lot and there's probably no definitive answer, but I want to generate five unique random numbers from a subset of numbers that is potentially infinite (maybe 0-20, or 0-1,000,000). The only catch is that I don't want to have to run while loops or fill an array. My current method is to simply generate five random numbers from a subset minus the last five numbers. If any of the numbers match each other, then they go to their respective place at the end of the subset. So if the fourth number matches any other number, it will bet set to the 4th from the last number. Does anyone have a method that is "random enough" and doesn't involve costly loops or arrays? Please keep in mind this a curiosity, not some mission-critical problem. I would appreciate it if everyone didn't post "why are you having this problem?" answers. I am just looking for ideas. Thanks a lot!

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• An efficient code to determine if a set is a subset of another set

  - by Edward

  I am looking for an efficient way to determine if a set is a subset of another set in Matlab or Mathematica. Example: Set A = [1 2 3 4] Set B = [4 3] Set C = [3 4 1] Set D = [4 3 2 1] The output should be: Set A Sets B and C belong to set A because A contains all of their elements, therefore, they can be deleted (the order of elements in a set doesn't matter). Set D has the same elements as set A and since set A precedes set D, I would like to simply keep set A and delete set D. So there are two essential rules: 1. Delete a set if it is a subset of another set 2. Delete a set if its elements are the same as those of a preceding set My Matlab code is not very efficient at doing this - it mostly consists of nested loops. Suggestions are very welcome! Additional explanation: the issue is that with a large number of sets there will be a very large number of pairwise comparisons.

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• Find subset with K elements that are closest to eachother

  - by Nima

  Given an array of integers size N, how can you efficiently find a subset of size K with elements that are closest to each other? Let the closeness for a subset (x1,x2,x3,..xk) be defined as: 2 <= N <= 10^5 2 <= K <= N constraints: Array may contain duplicates and is not guaranteed to be sorted. My brute force solution is very slow for large N, and it doesn't check if there's more than 1 solution: N = input() K = input() assert 2 <= N <= 10**5 assert 2 <= K <= N a = [] for i in xrange(0, N): a.append(input()) a.sort() minimum = sys.maxint startindex = 0 for i in xrange(0,N-K+1): last = i + K tmp = 0 for j in xrange(i, last): for l in xrange(j+1, last): tmp += abs(a[j]-a[l]) if(tmp > minimum): break if(tmp < minimum): minimum = tmp startindex = i #end index = startindex + K? Examples: N = 7 K = 3 array = [10,100,300,200,1000,20,30] result = [10,20,30] N = 10 K = 4 array = [1,2,3,4,10,20,30,40,100,200] result = [1,2,3,4]

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• An efficient code to determine if a set is a subset of another set

  - by Edward

  I am looking for an efficient way to determine if a set is a subset of another set in Matlab or Mathematica. Example: Set A = [1 2 3 4] Set B = [4 3] Set C = [3 4 1] Set D = [4 3 2 1] The output should be: Set A Sets B and C belong to set A because A contains all of their elements, therefore, they can be deleted (the order of elements in a set doesn't matter). Set D has the same elements as set A and since set A precedes set D, I would like to simply keep set A and delete set D. So there are two essential rules: 1. Delete a set if it is a subset of another set 2. Delete a set if its elements are the same as those of a preceding set My Matlab code is not very efficient at doing this - it mostly consists of nested loops. Suggestions are very welcome! Additional explanation: the issue is that with a large number of sets there will be a very large number of pairwise comparisons.

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• SQL To Filter A SubSet Of Data

  - by Nick LaMarca

  I have an arraylist that holds a subset of names found in my database. I need to write a query to get a count of the people in the arraylist for certain sections i.e. There is a field "City" in my database from the people in the arraylist of names I want to know how many of them live in Chicago, how many live in New York etc. Can someone help me how I might set up an sql statement to handle this. I think somehow I have to pass the subset of names to sql somehow.

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• R: Are there any alternatives to loops for subsetting from an optimization standpoint?

  - by Adam

  A recurring analysis paradigm I encounter in my research is the need to subset based on all different group id values, performing statistical analysis on each group in turn, and putting the results in an output matrix for further processing/summarizing. How I typically do this in R is something like the following: data.mat <- read.csv("...") groupids <- unique(data.mat$ID) #Assume there are then 100 unique groups results <- matrix(rep("NA",300),ncol=3,nrow=100) for(i in 1:100) { tempmat <- subset(data.mat,ID==groupids[i]) #Run various stats on tempmat (correlations, regressions, etc), checking to #make sure this specific group doesn't have NAs in the variables I'm using #and assign results to x, y, and z, for example. results[i,1] <- x results[i,2] <- y results[i,3] <- z } This ends up working for me, but depending on the size of the data and the number of groups I'm working with, this can take up to three days. Besides branching out into parallel processing, is there any "trick" for making something like this run faster? For instance, converting the loops into something else (something like an apply with a function containing the stats I want to run inside the loop), or eliminating the need to actually assign the subset of data to a variable?

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• Subset a data.frame by list and apply function on each part, by rows

  - by aL3xa

  This may seem as a typical plyr problem, but I have something different in mind. Here's the function that I want to optimize (skip the for loop). # dummy data set.seed(1985) lst <- list(a=1:10, b=11:15, c=16:20) m <- matrix(round(runif(200, 1, 7)), 10) m <- as.data.frame(m) dfsub <- function(dt, lst, fun) { # check whether dt is `data.frame` stopifnot (is.data.frame(dt)) # check if vectors in lst are "whole" / integer # vector elements should be column indexes is.wholenumber <- function(x, tol = .Machine$double.eps^0.5) abs(x - round(x)) < tol # fall if any non-integers in list idx <- rapply(lst, is.wholenumber) stopifnot(idx) # check for list length stopifnot(ncol(dt) == length(idx)) # subset the data subs <- list() for (i in 1:length(lst)) { # apply function on each part, by row subs[[i]] <- apply(dt[ , lst[[i]]], 1, fun) } # preserve names names(subs) <- names(lst) # convert to data.frame subs <- as.data.frame(subs) # guess what =) return(subs) } And now a short demonstration... actually, I'm about to explain what I primarily intended to do. I wanted to subset a data.frame by vectors gathered in list object. Since this is a part of code from a function that accompanies data manipulation in psychological research, you can consider m as a results from personality questionnaire (10 subjects, 20 vars). Vectors in list hold column indexes that define questionnaire subscales (e.g. personality traits). Each subscale is defined by several items (columns in data.frame). If we presuppose that the score on each subscale is nothing more than sum (or some other function) of row values (results on that part of questionnaire for each subject), you could run: > dfsub(m, lst, sum) a b c 1 46 20 24 2 41 24 21 3 41 13 12 4 37 14 18 5 57 18 25 6 27 18 18 7 28 17 20 8 31 18 23 9 38 14 15 10 41 14 22 I took a glance at this function and I must admit that this little loop isn't spoiling the code at all... BUT, if there's an easier/efficient way of doing this, please, let me know!

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• Complexity of subset product

  - by threenplusone

  I have a set of numbers produced using the following formula with integers 0 < x < a. f(x) = f(x-1)^2 % a For example starting at 2 with a = 649. {2, 4, 16, 256, 636, 169, 5, 25, 649, 576, 137, ...} I am after a subset of these numbers that when multiplied together equals 1 mod N. I believe this problem by itself to be NP-complete (based on similaries to Subset-Sum problem). However starting with any integer (x) gives the same solution pattern. Eg. a = 649 {2, 4, 16, 256, 636, 169, 5, 25, 649, 576, 137, ...} = 16 * 5 * 576 = 1 % 649 {3, 9, 81, 71, 498, 86, 257, 500, 135, 53, 213, ...} = 81 * 257 * 53 = 1 % 649 {4, 16, 256, 636, 169, 5, 25, 649, 576, 137, 597, ...} = 256 * 25 * 137 = 1 % 649 I am wondering if this additional fact makes this problem solvable faster? Or if anyone has run into this problem previously or has any advice?

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• /dev/sda1 not a subset of /dev/sda?

  - by Guillaume Brunerie

  Hi, the first entry of my partition table is: $ sudo hexdump -Cv -n 16 -s 446 /dev/sda 000001be 80 01 01 00 83 fe ff ff 3f 00 00 00 81 1c 20 03 |........?..... .| (-Cv describe the output format, -n 16 asks for 16 bytes and -s 446 skips the first 446 bytes) You can see that my first partition is a primary Linux partition and that this partition begin at sector 63 (see for example here for the structure of the partition table). I would then expect that except for the first 63 sectors and the other partitions, /dev/sda1 and /dev/sda are exactly the same. But this is not the case, the sector #2 of /dev/sda1 is not exactly the same as the sector #65 of /dev/sda (but they are very similar, only 16 bytes are different): $ sudo hexdump -Cv -n 512 -s 65b /dev/sda 00008200 00 20 19 00 90 03 64 00 2d 00 05 00 5a 2f 56 00 |. ....d.-...Z/V.| 00008210 b6 b1 16 00 00 00 00 00 02 00 00 00 02 00 00 00 |................| 00008220 00 80 00 00 00 80 00 00 00 20 00 00 d8 38 ee 4c |......... ...8.L| 00008230 9a 01 ef 4c 05 00 24 00 53 ef 01 00 01 00 00 00 |...L..$.S.......| 00008240 59 23 e9 4c 00 4e ed 00 00 00 00 00 01 00 00 00 |Y#.L.N..........| 00008250 00 00 00 00 0b 00 00 00 00 01 00 00 3c 00 00 00 |............<...| 00008260 42 02 00 00 7b 00 00 00 85 23 eb f2 71 67 44 f5 |B...{....#..qgD.| 00008270 bb 8f 6f f2 3a 59 ff 4d 55 62 75 6e 74 75 00 00 |..o.:Y.MUbuntu..| 00008280 00 00 00 00 00 00 00 00 2f 75 62 75 6e 74 75 00 |......../ubuntu.| 00008290 d8 3c df 5d 00 88 ff ff 52 d0 ef 1d 00 00 00 00 |.<.]....R.......| 000082a0 c0 40 51 b6 00 88 ff ff 00 4e c8 bb 00 88 ff ff |[email protected]......| 000082b0 c0 f6 86 b8 00 88 ff ff 30 2e 0d a0 ff ff ff ff |........0.......| 000082c0 38 3d df 5d 00 88 ff ff 00 00 00 00 00 00 fe 03 |8=.]............| 000082d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000082e0 08 00 00 00 00 00 00 00 00 00 00 00 8a 53 d3 0e |.............S..| 000082f0 7c 7a 43 e4 8b fb ca e0 72 b7 fa c8 01 01 00 00 ||zC.....r.......| 00008300 00 00 00 00 00 00 00 00 16 4c 47 4b 0a f3 03 00 |.........LGK....| 00008310 04 00 00 00 00 00 00 00 00 00 00 00 fe 7f 00 00 |................| 00008320 24 b7 0c 00 fe 7f 00 00 01 00 00 00 22 37 0d 00 |$..........."7..| 00008330 ff 7f 00 00 01 00 00 00 23 37 0d 00 00 00 00 00 |........#7......| 00008340 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 08 |................| 00008350 00 00 00 00 00 00 00 00 00 00 00 00 1c 00 1c 00 |................| 00008360 01 00 00 00 e9 7f 00 00 00 00 00 00 00 00 00 00 |................| 00008370 00 00 00 00 04 00 00 00 9f 7d bb 00 00 00 00 00 |.........}......| 00008380 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00008390 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| versus $ sudo hexdump -Cv -n 512 -s 2b /dev/sda1 00000400 00 20 19 00 90 03 64 00 2d 00 05 00 5a 2f 56 00 |. ....d.-...Z/V.| 00000410 b6 b1 16 00 00 00 00 00 02 00 00 00 02 00 00 00 |................| 00000420 00 80 00 00 00 80 00 00 00 20 00 00 df 76 ef 4c |......... ...v.L| 00000430 df 76 ef 4c 06 00 24 00 53 ef 01 00 01 00 00 00 |.v.L..$.S.......| 00000440 59 23 e9 4c 00 4e ed 00 00 00 00 00 01 00 00 00 |Y#.L.N..........| 00000450 00 00 00 00 0b 00 00 00 00 01 00 00 3c 00 00 00 |............<...| 00000460 46 02 00 00 7b 00 00 00 85 23 eb f2 71 67 44 f5 |F...{....#..qgD.| 00000470 bb 8f 6f f2 3a 59 ff 4d 55 62 75 6e 74 75 00 00 |..o.:Y.MUbuntu..| 00000480 00 00 00 00 00 00 00 00 2f 75 62 75 6e 74 75 00 |......../ubuntu.| 00000490 d8 3c df 5d 00 88 ff ff 52 d0 ef 1d 00 00 00 00 |.<.]....R.......| 000004a0 c0 40 51 b6 00 88 ff ff 00 4e c8 bb 00 88 ff ff |[email protected]......| 000004b0 c0 f6 86 b8 00 88 ff ff 30 2e 0d a0 ff ff ff ff |........0.......| 000004c0 38 3d df 5d 00 88 ff ff 00 00 00 00 00 00 fe 03 |8=.]............| 000004d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000004e0 08 00 00 00 00 00 00 00 00 00 00 00 8a 53 d3 0e |.............S..| 000004f0 7c 7a 43 e4 8b fb ca e0 72 b7 fa c8 01 01 00 00 ||zC.....r.......| 00000500 00 00 00 00 00 00 00 00 16 4c 47 4b 0a f3 03 00 |.........LGK....| 00000510 04 00 00 00 00 00 00 00 00 00 00 00 fe 7f 00 00 |................| 00000520 24 b7 0c 00 fe 7f 00 00 01 00 00 00 22 37 0d 00 |$..........."7..| 00000530 ff 7f 00 00 01 00 00 00 23 37 0d 00 00 00 00 00 |........#7......| 00000540 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 08 |................| 00000550 00 00 00 00 00 00 00 00 00 00 00 00 1c 00 1c 00 |................| 00000560 01 00 00 00 e9 7f 00 00 00 00 00 00 00 00 00 00 |................| 00000570 00 00 00 00 04 00 00 00 a3 7d bb 00 00 00 00 00 |.........}......| 00000580 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000590 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| For example in the third line, there is a 8.L in the first hexdump and v.L in the second. Why are there differences?

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• Allow Windows Domain users Local Admin rights on subset of Domain Computers

  - by growse

  I'm a bit new to AD management, so would appreciate some help in what may be a very simple task. I've got a domain that manages a bunch of different servers, and I want to grant local administrative rights to some domain users to some of the servers (the development webservers). I appreciate the group concept, so I imagine I would have to create a group containing the users in question another group containing the computers to grant them access to. What's the best way of going about this?

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• Wireless dropouts that only affect subset of devices

  - by jwaddell

  When watching videos streamed over WiFi from a NAS box (D-Link DNS-323) I am getting wireless dropouts. However they only appear to occur when I have left my laptop (Dell Inspiron 9300 running Windows XP SP3) running; the laptop is usually suspended if I'm not using it. The dropouts have occurred when streaming to a Netgear EVA8000 streaming device, and also to a PS3. I'm using a Netgear DG834G as the wireless modem/router. When a dropout occurs I go to the laptop and see that its wireless connection has also dropped out. The odd thing is that my wife's MacBook and my iPhone still maintain their connections. What could be causing this behaviour, and how do I go about fixing it?

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• Expose subset of a class - design question

  - by thanikkal

  Suppose i have a product class with about close to 100 properties. Now for some operations (Say tax calculation) i dont really need this bulky product type, rather only a subset that has price related properties. I am not sure if i should create different snap shots(class) of products that just has the properties that i am interested in. what would be the ideal approach so that i don't unnecessarily pass around unsought fluff? Thanks in advance.

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• Is .NET Compact a perfect subset of .NET?

  - by Andrew J. Brehm

  Is .NET Compact a perfect subset of .NET? Can I write a Windows Forms application and run it on .NET Compact, assuming that I took into account screen size and other limitations and avoid classes and methods not supported by .NET Compact or is .NET Compact a diffent and incompatible GUI framework?

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• Count subset of binary pattern ..

  - by mr.bio

  Hi there . I have a A=set of strings and a B=seperate string. I want to count the number of occurences in from B in A. Example : A: 10001 10011 11000 10010 10101 B: 10001 result would be 3.(10001 is a subset of 10001,10011,10101) So i need a function that takes a set and string and returns an int. int myfunc(set<string> , string){ int result; // My Brain is melting return result ; }

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• Filtering subsets using Linq

  - by Nathan Matthews

  Hi All, Imagine a have a very long enunumeration, too big to reasonably convert to a list. Imagine also that I want to remove duplicates from the list. Lastly imagine that I know that only a small subset of the initial enumeration could possibly contain duplicates. The last point makes the problem practical. Basically I want to filter out the list based on some predicate and only call Distinct() on that subset, but also recombine with the enumeration where the predicate returned false. Can anyone think of a good idiomatic Linq way of doing this? I suppose the question boils down to the following: With Linq how can you perform selective processing on a predicated enumeration and recombine the result stream with the rejected cases from the predicate?

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• Select a subset of foreign key elements in inlineformset_factory in Django

  - by Enis Afgan

  Hello, I have a model with two foreign keys: class Model1(models.Model): model_a = models.ForeignKey(ModelA) model_b = models.ForeignKey(ModelB) value = models.IntegerField() Then, I create an inline formset class, like so: an_inline_formset = inlineformset_factory(ModelA, Model1, fk_name="model_a") and then instantiate it, like so: a_formset = an_inline_formset(request.POST, instance=model_A_object) Once this formset gets rendered in a template/page, there is ChoiceField associated with the model_b field. The problem I'm having is that the elements in the resulting drop down menu include all of the elements found in ModelB table. I need to select a subset of those based on some criteria from ModelB. At the same time, I need to keep the reference to the instance of model_A_object when instantiating inlineformset_factory and, therefore, I can't just use this example. Any suggestions?

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• SELECT subset from two tables and LEFT JOIN results

  - by Doctor Trout

  Hi all, I'm trying to write a bit of SQL for SQLITE that will take a subset from two tables (TableA and TableB) and then perform a LEFT JOIN. This is what I've tried, but this produces the wrong result: Select * from TableA Left Join TableB using(key) where TableA.key2 = "xxxx" AND TableB.key3 = "yyyy" This ignore cases where key2="xxxx" but key3 != "yyyy". I want all the rows from TableA that match my criteria whether or not their corresponding value in TableB matches, but only those rows from TableB that match both conditions. I did manage to solve this by using a VIEW, but I'm sure there must be a better way of doing this. It's just beginning to drive me insane tryng to solve it now. (Thanks for any help, hope I've explained this well enough).

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• Plotting andrews curves of subsets of a data frame on the same plot

  - by user2976477

  I have a data frame of 12 columns and I want to plot andrews curves in R of this data, basing the color of the curves on the 12th columns. Below are a few samples from the data (sorry the columns are not aligned with the numbers) Teacher_explaining Teacher_enthusiastic Teacher_material_interesting Material_stimulating Material_useful Clear_marking Marking_fair Feedback_prompt Feedback_clarifies Detailed_comments Notes Year 80 80 80 80 85 85 80 80 80 80 70 3 70 60 30 40 70 60 30 40 70 0 30 3 100 90 90 80 80 100 100 90 100 100 100 MSc 85 85 85 90 90 70 90 50 70 80 100 MSc 90 50 90 90 90 70 100 50 80 100 100 4 100 80 80 75 90 80 80 50 80 80 90 3 From this data I tried to plot andrews curves using the code below: install.packages("andrews") library(andrews) col <- as.numeric(factor(course[,12])) andrews(course[,1:12], clr = 12) However, the 12th column has three groups (3 types of responses) and I want to group two of them and then plot the andrews curve of the data, without editing my data frame in Excel. x <- subset(course, Year == "MSc" & "4") y <- subset(course, Year == "3") I tried the above code, but my argument for x don't work. "MSc", "3" and "4" are the groups in the 12th column, and I want to group MSc and 4 so that their Andrews curves have the same color. If you have any idea how to do this, please let me know.

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• sort django queryset by latest instance of a subset of related model

  - by rsp

  I have an Order model and order_event model. Each order_event has a foreignkey to order. so from an order instance i can get: myorder.order_event_set. I want to get a list of all orders but i want them to be sorted by the date of the last event. A statement like this works to sort by the latest event date: queryset = Order.objects.all().annotate(latest_event_date=Max('order_event__event_datetime')).order_by('latest_event_date') However, what I really need is a list of all orders sorted by latest date of A SUBSET OF EVENTS. For example my events are categorized into "scheduling", "processing", etc. So I should be able to get a list of all orders sorted by the latest scheduling event. This django doc (https://docs.djangoproject.com/en/dev/topics/db/aggregation/#filter-and-exclude) shows how I can get the latest schedule event using a filter but this excludes orders without a scheduling event. I thought I could combine the filtered queryset with a queryset that includes back those orders that are missing a scheduling event...but I'm not quite sure how to do this. I saw answers related to using python list but it would be much more useful to have a proper django queryset (ie for a view with pagination, etc.)

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• Fastest way to perform subset test operation on a large collection of sets with same domain

  - by niktech

  Assume we have trillions of sets stored somewhere. The domain for each of these sets is the same. It is also finite and discrete. So each set may be stored as a bit field (eg: 0000100111...) of a relatively short length (eg: 1024). That is, bit X in the bitfield indicates whether item X (of 1024 possible items) is included in the given set or not. Now, I want to devise a storage structure and an algorithm to efficiently answer the query: what sets in the data store have set Y as a subset. Set Y itself is not present in the data store and is specified at run time. Now the simplest way to solve this would be to AND the bitfield for set Y with bit fields of every set in the data store one by one, picking the ones whose AND result matches Y's bitfield. How can I speed this up? Is there a tree structure (index) or some smart algorithm that would allow me to perform this query without having to AND every stored set's bitfield? Are there databases that already support such operations on large collections of sets?

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• Copy subset of xml input using xslt

  - by mdfaraz

  I need an XSLT file to transform input xml to another with a subset of nodes in the input xml. For ex, if input has 10 nodes, I need to create output with about 5 nodes Input <Department diffgr:id="Department1" msdata:rowOrder="0"> <Department>10</Department> <DepartmentDescription>BABY PRODUCTS</DepartmentDescription> <DepartmentSeq>7</DepartmentSeq> <InsertDateTime>2011-09-29T13:19:28.817-05:00</InsertDateTime> </Department> Output: <Department diffgr:id="Department1" msdata:rowOrder="0"> <Department>10</Department> <DepartmentDescription>BABY PRODUCTS</DepartmentDescription> </Department> I found one way to suppress nodes that we dont need XSLT: <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output omit-xml-declaration="yes"/> <xsl:template match="node()|@*"> <xsl:copy> <xsl:apply-templates select="node()|@*"/> </xsl:copy> </xsl:template> <xsl:template match="Department/DepartmentSeq"/> <xsl:template match="Department/InsertDateTime"/> </xsl:stylesheet> I need an xslt that helps me select the nodes I need and not "copy all and filter out what I dont need", since i may have to change my xslt whenever input schema adds more nodes.

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