Merge pull request satwikkansal#192 from Jongy/correctify-stubborn-del-explanation

satwikkansal · web-flow · commit 669ff8c30e65 · 2020-03-25T22:40:42.000+05:30
Correctify explanation of "Stubborn `del` operation"
diff --git a/README.md b/README.md
@@ -1954,7 +1954,7 @@ class SomeClass:
 Deleted!
 ```
 
-Phew, deleted at last. You might have guessed what saved from `__del__` being called in our first attempt to delete `x`. Let's add more twists to the example.
+Phew, deleted at last. You might have guessed what saved `__del__` from being called in our first attempt to delete `x`. Let's add more twists to the example.
 
 2\.
 ```py
@@ -1973,9 +1973,9 @@ Okay, now it's deleted :confused:
 
 #### 💡 Explanation:
 + `del x` doesn’t directly call `x.__del__()`.
-+ Whenever `del x` is encountered, Python decrements the reference count for `x` by one, and `x.__del__()` when x’s reference count reaches zero.
-+ In the second output snippet, `y.__del__()` was not called because the previous statement (`>>> y`) in the interactive interpreter created another reference to the same object, thus preventing the reference count from reaching zero when `del y` was encountered.
-+ Calling `globals` caused the existing reference to be destroyed, and hence we can see "Deleted!" being printed (finally!).
++ When `del x` is encountered, Python deletes the name `x` from current scope and decrements by 1 the reference count of the object `x` referenced. `__del__()` is called only when the object's reference count reaches zero.
++ In the second output snippet, `__del__()` was not called because the previous statement (`>>> y`) in the interactive interpreter created another reference to the same object (specifically, the `_` magic variable which references the result value of the last non `None` expression on the REPL), thus preventing the reference count from reaching zero when `del y` was encountered.
++ Calling `globals` (or really, executing anything that will have a non `None` result) caused `_` to reference the new result, dropping the existing reference. Now the reference count reached 0 and we can see "Deleted!" being printed (finally!).
 
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