You can read about the changes in What’s New In Python 3.0. You should read it thoroughly when you move from 2.x to 3.x since a lot has been changed. The whole answer here are quotes from the documentation. Views And Iterators Instead Of Lists Some well-known APIs no longer return lists: […] map() and filter() return iterators. If … Read more
Suppose you are designing a new class with some methods that you don’t want to implement, yet. If you were to leave out the pass, the code wouldn’t run. You would then get an: To summarize, the pass statement does nothing particular, but it can act as a placeholder, as demonstrated here.
You can make use of the reversed function for this as: Note that reversed(…) does not return a list. You can get a reversed list using list(reversed(array)).
The effects of the three different methods to remove an element from a list: remove removes the first matching value, not a specific index: del removes the item at a specific index: and pop removes the item at a specific index and returns it. Their error modes are different too:
should be: You are multiplying 0.01 with the growthRates list object. Multiplying a list by an integer is valid (it’s overloaded syntactic sugar that allows you to create an extended a list with copies of its element references). Example:
shutil has many methods you can use. One of which is: Copy the contents of the file named src to a file named dst. Both src and dst need to be the entire filename of the files, including path. The destination location must be writable; otherwise, an IOError exception will be raised. If dst already exists, it will be replaced. Special files such as character or block … Read more
How do I manually throw/raise an exception in Python? Use the most specific Exception constructor that semantically fits your issue. Be specific in your message, e.g.: Don’t raise generic exceptions Avoid raising a generic Exception. To catch it, you’ll have to catch all other more specific exceptions that subclass it. Problem 1: Hiding bugs For example: … Read more
How can I do the following in Python? I need to have the elements of an array, but from the end to the beginning.
shutil has many methods you can use. One of which is: Copy the contents of the file named src to a file named dst. Both src and dst need to be the entire filename of the files, including path. The destination location must be writable; otherwise, an IOError exception will be raised. If dst already exists, it will be replaced. Special files such as character or block … Read more
Use .lower() – For example: The official 2.x documentation is here: str.lower()The official 3.x documentation is here: str.lower()