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Add new example: Counting the booleans
* Moves the "Booleans are subclass of int" example from "Minor Ones" list to a new example.
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README.md
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README.md
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@ -1377,6 +1377,44 @@ Before Python 3.5, the boolean value fo `datetime.time` object was considered to
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---
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### Counting the booleans
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```py
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# A simple example to count the number of boolean and
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# integers in an iterable of mixed data types.
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mixed_list = [False, 1.0, "some_string", 3, True, [], False]
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integers_found_so_far = 0
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booleans_found_so_far = 0
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for item in mixed_list:
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if isinstance(item, int):
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integers_found_so_far += 1
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elif isinstance(item, bool):
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booleans_found_so_far += 1
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```
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**Outuput:**
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```py
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>>> booleans_found_so_far
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0
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>>> integers_found_so_far
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4
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```
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#### 💡 Explanation:
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* Booleans are a subclass of `int`
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```py
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>>> isinstance(True, int)
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True
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>>> isinstance(False, int)
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True
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```
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* See this StackOverflow [answer](https://stackoverflow.com/a/8169049/4354153) for rationale behind it.
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---
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### Needle in a Haystack
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Almost every Python programmer would have faced this situation.
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@ -1508,13 +1546,7 @@ a, b = a[b] = {}, 5
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+ `[] = ()` is a semantically correct statement (unpacking an empty `tuple` into an empty `list`)
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+ `'a'[0][0][0][0][0]` is also a semantically correct statement as strings are iterable in Python.
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+ `3 --0-- 5 == 8` and `--5 == 5` are both semantically correct statments and evalute to `True`.
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* Booleans are a subclass of `int`
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```py
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>>> isinstance(True, int)
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True
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>>> isinstance(True, float)
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False
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```
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* Python uses 2 bytes for local variable storage in functions. In theory, this means that only 65536 variables can be defined in a function. However, python has a handy solution built in that can be used to store more than 2^16 variable names. The following code demonstrates what happens in the stack when more than 65536 local variables are defined (Warning: This code prints around 2^18 lines of text, so be prepared!):
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```py
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import dis
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