So I am curious lets say I have a class as follows
parts = 1
to = 2
a = 3
whole = 4
self.contents = [parts,to,a,whole]
Never, unless you are very tight on memory and doing something very bulky. If you are writing usual program, garbage collector should take care of everything.
If you are writing something bulky, you should know that
del does not delete the object, it just dereferences it. I.e. variable no longer refers to the place in memory where object data is stored. After that it still needs to be cleaned up by garbage collector in order for memory to be freed (that happens automatically).
There is also a way to force garbage collector to clean objects -
gc.collect(), which may be useful after you ran
del. For example:
import gc a = [i for i in range(1, 10 ** 9)] ... del a # Object [0, 1, 2, ..., 10 ** 9 - 1] is not reachable but still in memory gc.collect() # Object deleted from memory
Update: really good note in comments. Watch for other references to the object in memory. For example:
import gc a = [i for i in range(1, 10 ** 9)] b = a ... del a gc.collect()
After execution of this block, the large array is still reachable through
b and will not be cleaned.