grep -Fxv -f first-file.txt second-file.txt Basically looks for all lines in second-file.txt which don’t match any line in first-file.txt. Might be slow if the files are large. Also, once you sort the files (Use sort -n if they are numeric), then comm should also have worked. What error does it give? Try this: comm -23 … Read more
It’s hard to compare semantics in the void. (What other languages do you mean?) A “module” might be analogous to a Java class, or a Java package, or something else entirely, depending on that other language. Typically since “modules” tend to be from procedural languages, I’d lean toward saying Java class, but I think the … Read more
Implementing equality in .NET correctly, efficiently and without code duplication is hard. Specifically, for reference types with value semantics (i.e. immutable types that treat equvialence as equality), you should implement the System.IEquatable<T> interface, and you should implement all the different operations (Equals, GetHashCode and ==, !=). As an example, here’s a class implementing value equality: … Read more
You should still do what is clearer, safer and easier to understand. These micro-tuning discussions are usually a waste of your time because they rarely make a measurable difference when they make a difference this can change if you use a different JVM, or processor. i.e. without warning. Note: the machine generated can also change … Read more
I found a really nice, free implementation at www.kellermansoftware.com called Compare .NET Objects which can be found here. Highly recommended. Appears to have relocated to github – most recent version is available here
sort($a); sort($b); if ($a===$b) {//equal}
If the types compared are the same, they are identical. That is to say they use the exact same algorithm. If the types are different, then performance is irrelevant. Either you need type coercion, or you don’t. If you don’t need it, don’t use == because the result you get may be unexpected.
One thing that slows down the VC++ compiler is if you have a header file that initializes concrete instances of non-trival const value types. You may see this happen with constants of type std::string or GUIDs. It affects both compilation and link time. For a single dll, this caused a 10x slowdown. It helps if … Read more
You need not to use std::sort. It can be done in a simpler way: if ( std::adjacent_find( myvector.begin(), myvector.end(), std::not_equal_to<>() ) == myvector.end() ) { std::cout << “All elements are equal each other” << std::endl; }