I am currently cleaning up a complex Python script and need to comment out large blocks of code for testing. I know that the hash symbol (#) works for single lines, but is there a specific syntax for multi-line comments? I’ve seen some developers use triple quotes, while others suggest using IDE keyboard shortcuts. Could someone clarify the standard practice and whether using triple quotes has any impact on the script’s performance or memory usage?
3 answers
In Python, there isn't technically a specific "multi-line comment" block like in C++ or Java. The most common and PEP 8-compliant way is to simply use a hash symbol # at the start of every line. While it seems tedious, most modern IDEs allow you to highlight a block and press Ctrl + / (Windows) or Cmd + / (Mac) to do this instantly. This is the preferred method because triple quotes """ are actually string literals (docstrings). If they aren't assigned to a variable, Python ignores them, but they are still processed by the interpreter, which can slightly affect memory if used excessively throughout a large software development project.
That’s a very clear distinction between comments and string literals! However, if I use triple quotes at the very beginning of a function or class definition, doesn't that serve a functional purpose for documentation tools like Sphinx or the built-in help() function? I'm curious if we should avoid triple quotes entirely for temporary code removal and save them strictly for formal documentation.
I always tell my juniors to use the IDE shortcuts for blocking out code. It’s faster, cleaner, and ensures that you aren't accidentally creating multi-line strings that might take up unnecessary space in the bytecode.
I agree with Jennifer. I used to use triple quotes for convenience, but after a code review at my current firm, I learned that sticking to the # symbol is the only way to ensure 100% compliance with PEP 8 standards. It makes the code much more readable for anyone else jumping into the repository later.
Steven, you are spot on. Triple quotes should be reserved for docstrings, which provide a high-level overview of what a function or class does. When you use them there, Python attaches that string to the __doc__ attribute of the object. For simply "hiding" code while debugging, stick to the hash symbol. Using docstrings for temporary comments is generally considered bad practice in professional environments because it can confuse automated documentation generators and other developers on your team.