Convert Year/Month/Day to Day of Year in Python
I’m using the datetime module, i.e.:
python
What is the purpose of subclassing the class “object” in Python?
All the Python built-ins are subclasses of object and I come across many user-defined classes which are too. Why? What is the purpose of the class object? It’s just an empty class, right?
What does hash do in python?
I saw an example of code that where hash function is applied to a tuple. As a result it returns a negative integer. I wonder what does this function do? Google does not help. I found a page that explains how hash is calculated but it does not explain why we need this function.
Matplotlib: draw grid lines behind other graph elements
In Matplotlib, I make dashed grid lines as follows:
Wrapping around a list as a slice operation
Consider the following simple python code
ValueError: Wrong number of items passed – Meaning and suggestions?
I am receiving the error:
ValueError: Wrong number of items passed 3, placement implies 1, and I am struggling to figure out where, and how I may begin addressing the problem.
Fastest way to search a list in python
When you do something like "test" in a where a is a list does python do a sequential search on the list or does it create a hash table representation to optimize the lookup? In the application I need this for I’ll be doing a lot of lookups on the list so would it be best to do something like b = set(a) and then "test" in b? Also note that the list of values I’ll have won’t have duplicate data and I don’t actually care about the order it’s in; I just need to be able to check for the existence of a value.
Axes class – set explicitly size (width/height) of axes in given units
I want to to create a figure using matplotlib where I can explicitly specify the size of the axes, i.e. I want to set the width and height of the axes bbox.