Use Expresso which gives a hierarchical, english breakdown of a regex. Or This tip from Darren Neimke: .NET allows regular expression patterns to be authored with embedded comments via the RegExOptions.IgnorePatternWhitespace compiler option and the (?#…) syntax embedded within each line of the pattern string. This allows for psuedo-code-like comments to be embedded in each … Read more
I’d nearly always prefer the local variable solution. Memory footprint A single local variable costs 4 or 8 bytes. It’s a reference and there’s no recursion, so let’s ignore it. Performance If this is a simple getter, the JVM can memoize it itself, so there’s no difference. If it’s a expensive call which can’t be … Read more
Consider what you are doing. You’re allocating memory. And if for some reason memory allocation cannot work, you assert. Which is more or less exactly what will happen if you just let the std::bad_alloc propagate back to main. In a release build, where assert is a no-op, your program will crash when it tries to … Read more
Using String concatenation is translated into StringBuilder operations by the compiler. To see how the compiler is doing I’ll take a sample class, compile it and decompile it with jad to see what’s the generated bytecode. Original class: public void method1() { System.out.println(“The answer is: ” + 42); } public void method2(int value) { System.out.println(“The … Read more
From PSR-2: Visibility MUST be declared on all properties and methods; abstract and final MUST be declared before the visibility; static MUST be declared after the visibility. [reference] …if you are one to care about the PHP Framework Interop Group standard and conventions. So public static not static public according to them.
In Perl Best Practices, the advice is to never use unless. Personally, I think that’s lunacy. I use unless whenever there’s a simple condition that I would otherwise write as if( ! … ). I find the unless version to be more readable, especially when used as a postfix: do_something() unless $should_not_do_that; I recommend avoiding … Read more
Life saver: as you’re writing your notebooks, incrementally refactor your code into functions, writing some minimal assert tests and docstrings. After that, refactoring from notebook to script is natural. Not only that, but it makes your life easier when writing long notebooks, even if you have no plans to turn them into anything else. Basic … Read more
The statement is ridiculous. continue can be abused, but it often helps readability. Typical use: for (somecondition) { if (!firsttest) continue; some_provisional_work_that_is_almost_always_needed(); if (!further_tests()) continue; do_expensive_operation(); } The goal is to avoid ‘lasagna’ code, where you have deeply nested conditionals. Edited to add: Yes, this is ultimately subjective. Here’s my metric for deciding. Edited one … Read more
Use a comparison to None if that’s what you want. Use “if not value” if you just want to check if the value is considered false (empty list, none, false). I find “if not value” to be cleaner looking and Pythonic. Also, be careful with lists. You should not use is when comparing for an … Read more
To my knowledge they are identical. I think there maybe a few engines out there that don’t support the numbered syntax but I’m not sure which. I vaguely recall a question on SO a few days ago where explicit notation wouldn’t work in Notepad++. The only time I would use explicitly numbered repetition is when … Read more