What is the id( ) function used for?

Question

I read the Python 2 docs and noticed the id() function:

Return the “identity” of an object. This is an integer (or long integer) which is

Answer 1

I'm a little bit late and i will talk about Python3. To understand what id() is and how it (and Python) works, consider next example:

>>> x=1000
>>> y=1000
>>> id(x)==id(y)
False
>>> id(x)
4312240944
>>> id(y)
4312240912
>>> id(1000)
4312241104
>>> x=1000
>>> id(x)
4312241104
>>> y=1000
>>> id(y)
4312241200

You need to think about everything on the right side as objects. Every time you make assignment - you create new object and that means new id. In the middle you can see a "wild" object which is created only for function - id(1000). So, it's lifetime is only for that line of code. If you check the next line - you see that when we create new variable x, it has the same id as that wild object. Pretty much it works like memory address.