a = (1) b = (1) a is b
>>> a = (1)
>>> b = (1)
>>> a is b
True
In the code snippet above, both a and b are defined as integers within parentheses. However, it's important to note that using parentheses around a single value in Python does not create a tuple; instead, it simply groups the value or expression.
Regarding the statement a is b, it checks if a and b refer to the same object in memory. However, due to the implementation details of Python's object caching for small integers, the result may vary.
Python object caching refers to the practice of storing and reusing objects in memory to improve performance and efficiency. Caching can be useful when the creation or computation of an object is time-consuming or resource-intensive, and the object is expected to be accessed multiple times.
In CPython, for small integers in the range [-5, 256], Python caches and reuses the objects. So, when you define a and b as 1, they both refer to the same object in memory. In this case, a is b would evaluate to True.
>>> a = (257)
>>> b = (257)
>>> a is b
False
However, for larger integers or when the caching range is exceeded, Python creates separate objects for each occurrence of the integer value. In such cases, a is b would evaluate to False.
To ensure consistent behavior, it is recommended to use the == operator for comparing values rather than is, unless you specifically need to check object identity.
0x09. Python - Everything is object
24-answer.txt