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Variables in Python can hold values of any type, and you can't restrict that. Your question specifically asks about classes, objects and instance variables though. The idiomatic way to create instance variables is in the __init__ method and nowhere else — while you could create new instance variables in other methods, or even in unrelated ...
In python it helps to think of declaring variables as binding values to names. Try not to misspell them, or you will have new ones (assuming you are talking about assignment statements - referencing them will cause an exception). If you are talking about instance variables, you won't be able to use them afterwards.
Apparently Python 2.7 has dictionary comprehensions, which would make for an extremely concise way to implement that function. This is left as an exercise to the reader, since I don't have Python 2.7 installed :) You can also combine some functions from the ever-versatile itertools module. As they say, There's More Than One Way To Do It. Wait ...
In Python, variables that are only referenced inside a function are implicitly global. If a variable is assigned a new value anywhere within the function’s body, it’s assumed to be a local. If a variable is ever assigned a new value inside the function, the variable is implicitly local, and you need to explicitly declare it as ‘global’.
PEP 526 aims at adding syntax to Python for annotating the types of variables (including class variables and instance variables), instead of expressing them through comments: captain: str # Note: no initial value!
I know Python is a dynamic language and declaring variables before-hand is generally not necessary, but in the case where I need to create a variable and then give it a value later, both of the following methods work: some_variable = '' some_variable = str() Is there a difference between both of these and which is considered best practice? Example:
One of the main utilities of functions is exactly the way they allow one to isolate variables - no worries about clashing names for the code in various functions - once a function works properly, it is done. But if one needs to expose variables that populated inside functions to the outside world, it is possible with the keyword "global ...
I noticed that in Python, people initialize their class attributes in two different ways. The first way is like this: class MyClass: __element1 = 123 __element2 = "this is Africa" def __init__(self): #pass or something else
If you assign the variable without the global keyword then Python creates a new local var -- the module variable's value will now be hidden inside the function. Use the global keyword to assign the module var inside a function. Pylint 1.3.1 under Python 2.7 enforces NOT using global if you don't assign the var.
Python assigning multiple variables to same value? list behavior concerned with tuples, I want just variables may be a string, integer or dictionary; More elegant way of declaring multiple variables at the same time The question has something I want to ask, but the accepted answer is much complex; so what I'm trying to achieve,