In a comment on this question, I saw a statement that recommended using result is not None vs result != None What is the difference? And why might one be recommended over the other? In Python 3, your example range (N) [::step] produces a range object, not a list. To really see what is happening, you need to coerce the range to a list, np.array, etc. What does the “at” (@) symbol do in Python? @ symbol is a syntactic sugar python provides to utilize decorator, to paraphrase the question, It's exactly about what does decorator do in Python? Put it simple decorator allow you to modify a given function's definition without touch its innermost (it's closure). Learn how to install the Pandas library in Visual Studio Code with step-by-step guidance from Stack Overflow. How do I write JSON data stored in the dictionary data to a file? f = open ('data.json', 'wb') f.write (data) This gives the error: TypeError: must be string or buffer, not dict To get high-precision timestamps in Python, see my answer here: High-precision clock in Python. How to iterate over Pandas DataFrame s without iterating After several weeks of working on this answer, here's what I've come up with: Here are 13 techniques for iterating over Pandas DataFrame s. As you can see, the time it takes varies dramatically. There's the != (not equal) operator that returns True when two values differ, though be careful with the types because 1 != 1. This will always return True and 1 == 1 will always return False, since the types differ. Python is dynamically, but strongly typed, and other statically typed languages would complain about comparing different types. There's also the else clause: In Python 3, we can use the below method. Read from a file and convert to JSON. The with statement automatically closes the opened file descriptor. String to JSON In Python this is simply =. To translate this pseudocode into Python you would need to know the data structures being referenced, and a bit more of the algorithm implementation. Some notes about psuedocode: := is the assignment operator or = in Python = is the equality operator or == in Python There are certain styles, and your mileage may vary: In python there is id function that shows a unique constant of an object during its lifetime. This id is using in back-end of Python interpreter to compare two objects using is keyword.