cartesian-product | 易学教程

Generate Combinations of generic list

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问题 I need to create a list from another list that contains every combination possible. In researching possible solutions I have found many interesting approaches but all seem to generate results based on the count of records provided. I need the combinations to increase to a max threshold. i.e. consider the following array 1,2,3,4,5 I need the results to look similar to (threshold is 3 in this example) 1 1,2 1,2,3 1,2,4 1,2,5 1,3,4 2,3,5... etc In actuality, the data will be IEnumerable. I used

C++ How to generate the set of cartesian product of n-dimensional tuples

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问题 I wish to generate some data that represents the co-ordinates of a cloud of points representing an n-cube of n dimensions. These points should be evenly distributed throughout the n-space and should be able to be generated with a user-defined spacing between them. This data will be stored in an array. 回答1: I have found an implementation of a cartesian product using Boost.MPL. There is an actual Cartesian product in Boost as well but that is a preprocessor directive, I assume it is of no use

How to combine two arrays as a cartesian product?

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问题 I have array1 = [1,2,3,4,5]; array2 = ["one","two","three","four","five"]; I want to get array3 where all elements of array1 with first (and others) element of array2 and etc. For example: array3 = ["one 1", "two 1", "three 1", "four 1", "five 1", "one 2", "two 2", "three 2", "four 2", "five 2"...] I understand that I need to use for loop but I don't know how to do it. 回答1: You can use two for-loops: var array1 = [1,2,3,4,5]; var array2 = ["one","two","three","four","five"]; var array3 = [];

Cartesian product in Scheme

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问题 I've been trying to do a function that returns the Cartesian Product of n sets,in Dr Scheme,the sets are given as a list of lists,I've been stuck at this all day,I would like a few guidelines as where to start. ----LATER EDIT ----- Here is the solution I came up with,I'm sure that it's not by far the most efficent or neat but I'm only studing Scheme for 3 weeks so be easy on me. 回答1: Here's a concise implementation that is also designed to minimize the size of the resulting structure in

How can I complete this Objective-C implementation of a cartesian product function?

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问题 As a follow up to my question here, I am trying to implement the following PHP function in Objective-C, which will generate a cartesian product: function array_cartesian_product($arrays) { $result = array(); $arrays = array_values($arrays); $sizeIn = sizeof($arrays); $size = $sizeIn > 0 ? 1 : 0; foreach ($arrays as $array) $size = $size * sizeof($array); for ($i = 0; $i < $size; $i ++) { $result[$i] = array(); for ($j = 0; $j < $sizeIn; $j ++) array_push($result[$i], current($arrays[$j]));

Generating list of 2-lists in Scheme

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(define cart-product (lambda (sos1 sos2) (if (null? sos1) '() (cons (cart-prod-sexpr (car sos1) sos2) (cart-product (cdr sos1) sos2))))) (define cart-prod-sexpr (lambda (s sos) (if (null? sos) '() (cons (list s (car sos)) (cart-prod-sexpr s (cdr sos)))))) Calling (cart-product '(q w) '(x y)) produces (((q x) (q y)) ((w x) (w y))) . How I can produce ((q x) (q y) (w x) (w y)) instead? Untested. Note that the append-list procedure I defined actually returns a list ending in sos2 . That is appropriate (and the right thing to do) here, but is not in general. (define cart-product (lambda (sos1 sos2

Jaccard Similarity of an RDD with the help of Spark and Scala without Cartesian?

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I am working on pair RDDs. My aim is to calculate jaccard similarity between the set of rdd values and cluster them according to the jaccard similarity threshold value.Structure of my RDD is : val a= [Key,Set(String)] //Pair RDD For example:- India,[Country,Place,....] USA,[Country,State,..] Berlin,[City,Popluatedplace,..] After finding jaccard similarity, I will cluster the similar entities into one cluster. In the above example, India and USA will be cluster into one cluster based on some threshold value whereas Berlin will be in the other cluster. So I took the Cartesian product of rdd a

How to generate the cartesian product of a jagged array?

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问题 I'm having some trouble figuring out how to generate the cartesian product of a jagged array. I have googled around, but i cant seem to find an implentation for a iterative language. So i'm trying to figure it out myself, but i've hit a snag. Lets define the problem a bit clearer Say i have an array of arrays which looks like this A = { {1}, {2, 3}, {4, 5, 6} } how do i go from that to B = { {1, 2, 4}, {1, 2, 5}, {1, 2, 6}, {1, 3, 4}, {1, 3, 5}, {1, 3, 6} } edit: Now this is just an example,

Algorithm to produce Cartesian product of arrays in depth-first order

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I'm looking for an example of how, in Ruby, a C like language, or pseudo code, to create the Cartesian product of a variable number of arrays of integers, each of differing length, and step through the results in a particular order: So given, [1,2,3],[1,2,3],[1,2,3]: [1, 1, 1] [2, 1, 1] [1, 2, 1] [1, 1, 2] [2, 2, 1] [1, 2, 2] [2, 1, 2] [2, 2, 2] [3, 1, 1] [1, 3, 1] etc. Instead of the typical result I've seen (including the example I give below): [1, 1, 1] [2, 1, 1] [3, 1, 1] [1, 2, 1] [2, 2, 1] [3, 2, 1] [1, 3, 1] [2, 3, 1] etc. The problem with this example is that the third position isn't

Postgresql: Insert the cartesian product of two or more sets

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问题 as definition: The cartesian product of two sets is the set of all possible pairs of these sets, so {A,B} x {a,b} = {(A,a),(A,b),(B,a),(B,b)}. Now i want to insert such a cartesian product into a database table (each pair as a row). It is intended to fill the table with default values for each pair, so the data, i.e. the two sets, are not present in the database at this point. Any idea how to achieve this with postgresql? EDIT : With the help of Grzegorz Szpetkowski's answer I was able to