Python: copy of a variable
copy, python, variables
Solution
You're exploring how Python deals with references. Assignment is simply binding a reference to an object on the right hand side. So, this is somewhat trivial:
a = 'foo'
b = a
print b is a #True -- They *are the same object*
However, as soon as you do:
b = 'bar'
b is a #False -- they're not longer the same object because you assigned a new object to b
Now this becomes really interesting with objects which are mutable:
a = [1]
b = a
b[0] = 'foo'
print a #What?? 'a' changed?
In this case, `a` changes because `b` and `a` are referencing the same object. When we make a change to `b` (which we can do since it is mutable), that same change is seen at `a` because they're the same object.
So, to answer your question, you can't do it directly, but you can do it indirectly if you used a mutable type (like a list) to store the actual data that you're carrying around.
This is something that is very important to understand when working with Python code, and it's not the way a lot of languages work, so it pays to really think about/research this until you truly understand it.
Problem
Is there a way in to make copy of a variable so that when the value changes of variable 'a' it copies itself to variable 'b'? Example ``` a='hello' b=a #.copy() or a function that will make a copy a='bye' # Is there a way to make # 'b' equal 'a' without # doing 'b=a' print a print b ``` I am having a problem using the Tkinter library where I have checkbutton that has been stored in a list and I'm trying to get the variable that it holds. But it takes around 5 lines of code to reach the variable. Is there a way of holding a copy of the variable that changes when the checkbutton variable changes?