python - What does "del" do exactly? - Stack Overflow
Python is a garbage-collected language. If a value isn't "reachable" from your code anymore, it will eventually get deleted. The del statement, as you saw, removes the binding of your variable. Variables aren't values, they're just names for values.
Difference between del, remove, and pop on lists in Python
2024年2月21日 · del removes references to Python objects, so as other answers mentioned, a slice of a list can be removed in one go, which is much faster than removing items one-by-one. In fact, if we perform a timeit test, removing a slice takes the same time as removing an item.
dictionary - When is del useful in Python? - Stack Overflow
2021年1月13日 · Yet another niche usage: In pyroot with ROOT5 or ROOT6, "del" may be useful to remove a python object that referred to a no-longer existing C++ object. This allows the dynamic lookup of pyroot to find an identically-named C++ object and bind it to the python name.
python - What is the __del__ method and how do I call it? - Stack …
'del is responsible for calling any del in a superclass, though it is not clear if this is in method resolution order (MRO) or just calling each superclass.': probably it needs to do a call to super() and if all base classes do the same, the whole mro is covered.
How does the `del` statement work in Python? - Stack Overflow
2013年2月19日 · del varname followed by Python’s garbage collector gc.collect() Regarding speed: Speed is the most important in applications such as financial applications with a regulatory requirement. You have to make sure that the speed of operation is …
del - I don't understand this python __del__ behaviour - Stack …
2017年5月1日 · del in the way you are using removes a local variable. __del__ is called when the object is destroyed. Python as a language makes no guarantees as to when it will destroy an object. CPython as the most common implementation of Python, uses reference counting. As a result del will often work as you expect.
How to delete multiple defined and undefined variables safely in …
2020年10月29日 · A one-liner to do del x safely: globals().pop('x', None); There are many ways to do that, but they need more than 1 line of code, which I guess is not what you look for.
python - Is the use of del bad? - Stack Overflow
2014年4月28日 · Particularly among new Python programmers, people do horrible things with while loops on functions (i.e., loop until you find a value that matches an input, del the index). Del requires an index as an input, and as soon as it is run, makes all existing indices referring to that list refer to entirely different data.
When am I supposed to use del in python? - Stack Overflow
2016年9月1日 · del may be useful if the algorithm employed by the garbage collection of your Python implementation delays the destruction of out-of-scope objects. E.g., you can read on PyPy's vs. CPython's implementations of garbage collections to see in which instances del may become useful (as a rule, very rarely). –
Python: del in for loop - Stack Overflow
2015年4月6日 · Assuming you want to print every number before removing them from the list. myList = [1,2,3] for n in test1: print n test1 = [n for n in myList if n % 2] # 0 = False by default in python.