Java generating non-repeating random numbers
For example:
duplicates
Remove duplicates from a List in C#
Perhaps you should consider using a HashSet. From the MSDN link:
How to remove all duplicates from an array of objects?
How about with some es6 magic? Reference URL A more generic solution would be: Using the above property strategy instead of JSON.stringify: You can add a wrapper if you want the propNames property to be either an array or a value: allowing both getUniqueItemsByProperties(‘a’) and getUniqueItemsByProperties([‘a’]); Stackblitz Example Explanation Start by understanding the two methods used: filter, findIndex Next take your idea of what … Read more
Shuffle a deck of cards in Java
Simply use a new array for the shuffled cards and fill it using random cards removed from the prior array. Or just use Collections.shuffle():
Remove duplicate rows in MySQL
A really easy way to do this is to add a UNIQUE index on the 3 columns. When you write the ALTER statement, include the IGNORE keyword. Like so: This will drop all the duplicate rows. As an added benefit, future INSERTs that are duplicates will error out. As always, you may want to take a backup before running something like this…
What’s the most efficient way to erase duplicates and sort a vector?
I agree with R. Pate and Todd Gardner; a std::set might be a good idea here. Even if you’re stuck using vectors, if you have enough duplicates, you might be better off creating a set to do the dirty work. Let’s compare three approaches: Just using vector, sort + unique Convert to set (manually) Convert to set (using a constructor) … Read more
Remove duplicate values from JS array
Quick and dirty using jQuery:
How do I check if there are duplicates in a flat list?
Use set() to remove duplicates if all values are hashable:
How do I find the duplicates in a list and create another list with them?
To remove duplicates use set(a). To print duplicates, something like: Note that Counter is not particularly efficient (timings) and probably overkill here. set will perform better. This code computes a list of unique elements in the source order: or, more concisely: I don’t recommend the latter style, because it is not obvious what not seen.add(x) is doing (the set add() method always returns None, hence … Read more
Fastest way to duplicate an array in JavaScript – slice vs. ‘for’ loop
There are at least 6 (!) ways to clone an array: loop slice Array.from() concat spread operator (FASTEST) map A.map(function(e){return e;}); There has been a huuuge BENCHMARKS thread, providing following information: for blink browsers slice() is the fastest method, concat() is a bit slower, and while loop is 2.4x slower. for other browsers while loop is the fastest method, since those browsers don’t have internal optimizations for slice and concat. This remains … Read more