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

Be carefull (concerning the answer just below)...That's only true because 123 is between -5 and 256...

In [111]: q = 257                                                         

In [112]: id(q)                                                            
Out[112]: 140020248465168

In [113]: w = 257                                                         

In [114]: id(w)                                                           
Out[114]: 140020274622544

In [115]: id(257)                                                         
Out[115]: 140020274622768