unique

问题 I am using rand() for a 6 digit field which needs unique values. Am I doing it right? What are the odds, rand() can give me similar values on consecutive or frequent calls? It was unique when I used rand(). But, returned same number when I called srand(time(NULL)) or srand(clock()) . Seems, like it's working opposite for me. Or is it? 回答1: As others have pointed out, uniqueness is not guaranteed. However you are probably seeing repeated numbers because you are using srand() and rand()

问题 How to remove duplicates from an ArrayList ? I have getCcnptags array as [java,php,c++,c,java,php] which i am getting from bean array, and I am giving hyper link to each array variable, but I want to remove duplicates before adding hyper link to it, does it possible to add any code in my below code to remove duplicates. for(int k=0;k<name.getCcnptags().size();k++) { String tag=name.getCcnptags().get(k); if(k!=name.getCcnptags().size()-1) { tag=tag+","; } %> <a href='#'><%=tag%></a> } 回答1:

问题 Given a std::vector<std::vector<int>> : I want to output a sorted std::vector<std::vector<int>> that contains only unique std::vector<int> as well as the frequency (i.e., count ) of these unique std::vector<int> My question is twofold: how can I efficiently achieve this relying only on the standard library? what is causing the code below to perform poorly? I tried the following: std::vector<std::vector<int>> responseVectors { { 2, 3, 2 }, { 3, 2, 3 }, { 3, 2, 3 }, { 3, 3, 3 }, { 1, 2, 3 }, {

问题 I've tried different workarounds that have been discussed here, but none of them are working in my case. This is my source: <div class="colourDots"> <img src="/out/pictures/generated/product/8/300_450_100/60028.bl.jpg"/><br> <img src="/out/pictures/generated/product/8/300_450_100/60028.bl.jpg"/><br> <img src="/out/pictures/generated/product/8/300_450_100/60028.bl.jpg"/><br> <img src="/out/pictures/generated/product/8/300_450_100/60028.sw.jpg"/><br> <img src="/out/pictures/generated/product/8

问题 It is possible to 'fill' an array in Python like so: > [0] * 10 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0] I wanted to use this sample principle to quickly create a list of similar objects: > a = [{'key': 'value'}] * 3 > a [{'key': 'value'}, {'key': 'value'}, {'key': 'value'}] But it appears these objects are linked with one another: > a[0]['key'] = 'another value' > a [{'key': 'another value'}, {'key': 'another value'}, {'key': 'another value'}] Given that Python does not have a clone() method (it was

问题 I have an array traced_descIDs containing object IDs and I want to identify which items are not unique in this array. Then, for each unique duplicate (careful) ID, I need to identify which indices of traced_descIDs are associated with it. As an example, if we take the traced_descIDs here, I want the following process to occur: traced_descIDs = [1, 345, 23, 345, 90, 1] dupIds = [1, 345] dupInds = [[0,5],[1,3]] I'm currently finding out which objects have more than 1 entry by: mentions = np

问题 I am trying to get Symfony's UniqueEntity validator working for my Doctrine entities. The Symfony validator is already hooked up and working, the UniqueEntity from Symfony\Bridge, however, is more challenging, displaying this error: PHP Fatal error: Class 'doctrine.orm.validator.unique' not found in /app/vendor/symfony/validator/Symfony/Component/Validator/ConstraintValidatorFactory.php on line 46 It appears as if the ValidatorFactory is requesting the UniqueEntity validator from the Symfony

问题 Using this method on a 8x8 matrix: >> [junk,index] = unique(data,'first'); %# Capture the index, ignore junk >> data(sort(index)) %# Index data with the sorted index Outputs the format in 64x1 format (if no repeats are found) or nx1 if some repeats are found. My question is how do I keep the matrix format without the sorting? i need it to check unique(rows) for duplicates not unique cells. And to delete the duplicate rows but keep the format (dont arrange/sort). 回答1: If you want unique rows,

问题 I have a data.frame with several columns (17). Column 2 have several rows with the same value, I want to keep only one of those rows, specifically the one that has the maximum value in column 17. For example: A B 'a' 1 'a' 2 'a' 3 'b' 5 'b' 200 Would return A B 'a' 3 'b' 200 (plus the rest of the columns) So far I've been using the unique function, but I think it randomly keeps one or keeps just the first one that appears. ** UPDATE ** The real data has 376000 rows. I've tried the data.table

问题 I have a data.frame with several columns (17). Column 2 have several rows with the same value, I want to keep only one of those rows, specifically the one that has the maximum value in column 17. For example: A B 'a' 1 'a' 2 'a' 3 'b' 5 'b' 200 Would return A B 'a' 3 'b' 200 (plus the rest of the columns) So far I've been using the unique function, but I think it randomly keeps one or keeps just the first one that appears. ** UPDATE ** The real data has 376000 rows. I've tried the data.table