Approach I wrote a benchmark program to evaluate different implementations: instanceof implementation (as reference) object-orientated via an abstract class and @Override a test method using an own type implementation getClass() == _.class implementation I used jmh to run the benchmark with 100 warmup calls, 1000 iterations under measuring, and with 10 forks. So each option … Read more
Use numpy.unique with return_counts=True (for NumPy 1.9+): import numpy as np x = np.array([1,1,1,2,2,2,5,25,1,1]) unique, counts = np.unique(x, return_counts=True) >>> print(np.asarray((unique, counts)).T) [[ 1 5] [ 2 3] [ 5 1] [25 1]] In comparison with scipy.stats.itemfreq: In [4]: x = np.random.random_integers(0,100,1e6) In [5]: %timeit unique, counts = np.unique(x, return_counts=True) 10 loops, best of 3: … Read more
Different Operators LIKE and = are different operators. Most answers here focus on the wildcard support, which is not the only difference between these operators! = is a comparison operator that operates on numbers and strings. When comparing strings, the comparison operator compares whole strings. LIKE is a string operator that compares character by character. … Read more
The Monte Carlo method, as mentioned, applies some great concepts but it is, clearly, not the fastest, not by a long shot, not by any reasonable measure. Also, it all depends on what kind of accuracy you are looking for. The fastest π I know of is the one with the digits hard coded. Looking … Read more
If all you need is the wall-clock time, rather than the CPU execution time, then it is simple to calculate: //place this before any script you want to calculate time $time_start = microtime(true); //sample script for($i=0; $i<1000; $i++){ //do anything } $time_end = microtime(true); //dividing with 60 will give the execution time in minutes otherwise … Read more
Basic Usage First, let’s see what each function does: regexObject.test( String ) Executes the search for a match between a regular expression and a specified string. Returns true or false. string.match( RegExp ) Used to retrieve the matches when matching a string against a regular expression. Returns an array with the matches or null if … Read more
This depends on the language being used. You wrote ‘language-agnostic’, so I’ll give some examples. In Java, C, and Python, recursion is fairly expensive compared to iteration (in general) because it requires the allocation of a new stack frame. In some C compilers, one can use a compiler flag to eliminate this overhead, which transforms … Read more
So I did some tests with sqlite for very large files, and came to some conclusions (at least for my specific application). The tests involve a single sqlite file with either a single table, or multiple tables. Each table had about 8 columns, almost all integers, and 4 indices. The idea was to insert enough … Read more
There are a number of methods of obtaining an execution plan, which one to use will depend on your circumstances. Usually you can use SQL Server Management Studio to get a plan, however if for some reason you can’t run your query in SQL Server Management Studio then you might find it helpful to be … Read more
MongoDB is not magically faster. If you store the same data, organised in basically the same fashion, and access it exactly the same way, then you really shouldn’t expect your results to be wildly different. After all, MySQL and MongoDB are both GPL, so if Mongo had some magically better IO code in it, then … Read more