[Unpacking, Generators, Bin/Ox/Hex Concepts]: Typo & Formatting Fixes (exercism#4186)

* Typo and formatting fixes in concept docs.

* Took care of the generator-iterator thingy.

Author: BethanyG

concepts/binary-octal-hexadecimal/about.md

@@ -18,7 +18,7 @@ A snippet from the base 2 system looks like this, although it continues infinite
 | -------- | -------- | -------- | -------- | -------- | -------- | -------- | -------- |
 | 2 \*\* 7 | 2 \*\* 6 | 2 \*\* 5 | 2 \*\* 4 | 2 \*\* 3 | 2 \*\* 2 | 2 \*\* 1 | 2 \*\* 0 |
 
-So if we want to represent the number 6, it would in binary be: 110
+So if we want to represent the number 6 in binary, it would be 110.
 
 | Place value   | 4   | 2   | 1   |
 | ------------- | --- | --- | --- |
@@ -41,7 +41,6 @@ In Python, we can represent binary literals using the `0b` prefix.
 If we write `0b10011`, Python will interpret it as a binary number and convert it to base 10.
 
 ```python
-# 0b10011
 >>> 0b10011
 19
 
@@ -86,6 +85,8 @@ However, the usual mathematical operator rules apply:  dividing two binary numbe
 
 >>> 0b10011/3
 6.333333333333333
+```
+
 
 ### Converting to and from Binary Representation
 
@@ -133,6 +134,9 @@ For example, `bit_count()` on '0b11011' will return 4:
 ```python
 >>> 0b11011.bit_count()
 4
+```
+
+
 ~~~~exercism/note
 If you are working locally, `bit_count()` requires at least Python 3.10.
 The Exercism online editor currently supports all features through Python 3.11.
@@ -148,7 +152,6 @@ In Python, we can represent octal numbers using the `0o` prefix.
 As with binary, Python automatically converts an octal representation to an `int`.
 
 ```python
-# 0o123
 >>> 0o123
 83
 ```
@@ -157,14 +160,15 @@ As with binary, octal numbers **are ints** and support all integer operations.
 Prefixing a number with `0o` that is not in the octal system will raise a `SyntaxError`.
 
  ### Converting to and from Octal Representation
- 
 
 To convert an `int` into an octal representation, you can use the built-in [`oct()`][oct] function.
 This acts similarly to the `bin()` function, returning a string:
 
 ```python
 >>> oct(83)
 '0o123'
+```
+
 
 To convert an octal number to an integer, we can use the `int()` function, passing an octal string representation and the base (8) as arguments:
 
@@ -175,22 +179,21 @@ To convert an octal number to an integer, we can use the `int()` function, passi
 
 As with binary, giving the wrong base will raise a `ValueError`.
 
-### Hexadecimal
+## Hexadecimal
 
 [Hexadecimal][hexadecimal] is a base 16 numeral system.
 It uses the digits 0 - 9 and the letters A, B, C, D, E, and F.
 A is 10, B is 11, C is 12, D is 13, E is 14, and F is 15.
 
 We can represent hexadecimal numbers in Python using the `0x` prefix.
-As with binary and octal, Python will automatically convert hexadecimal literals to `int`.
+As with binary and octal, Python will automatically convert hexadecimal literals to `int`s.
 
 ```python
-# 0x123
 >>> 0x123
 291
 ```
 
-As with binary and octal - hexadecimal literals **are ints**, and you can perform all integer operations.  
+As with binary and octal — hexadecimal literals **are ints**, and you can perform all integer operations with them.
 Prefixing a non-hexadecimal number with `0x` will raise a `SyntaxError`.
 
 
@@ -202,6 +205,8 @@ This acts similarly to the `bin()` function, returning a string:
 ```python
 >>> hex(291)
 '0x123'
+```
+
 
 To convert a hexadecimal representation to an integer, we can use the `int()` function, passing a hexadecimal string with the base (16) as arguments:
 

concepts/binary-octal-hexadecimal/introduction.md

@@ -1,4 +1,4 @@
-# binary, octal, hexadecimal
+# Binary, Octal, Hexadecimal
 
 Binary, octal, and hexadecimal (_also known as hex_) are different [numeral systems][numeral-systems] with different bases.
 Binary is base 2, octal is base 8, and hexadecimal is base 16.

concepts/generators/about.md

@@ -35,9 +35,33 @@ The rationale behind this is that you use a generator when you do not need all t
 
 This saves memory and processing power, since only the value you are _currently working on_ is calculated.
 
+
 ## Using a generator
 
-Generators may be used in place of most `iterables` in Python. This includes _functions_ or _objects_ that require an `iterable`/`iterator` as an argument.
+Generators (_technically [`generator-iterator`s][generator-iterator] — see the note below._) are a type of `iterator` and can be used anywhere in Python where an `iterator` or `iterable` is expected.
+This includes _functions_ or _objects_ that require an `iterable`/`iterator` as an argument.
+For a deeper dive, see [How to Make an Iterator in Python][how-to-iterator].
+
+
+~~~~exercism/note
+
+Generator-iterators are a special sub-set of [iterators][iterator].
+`Iterators` are the mechanism/protocol that enables looping over _iterables_.
+Generator-iterators and the iterators returned by common Python [`iterables`][iterables] act very similarly, but there are some important differences to note:
+
+- They are _[lazily evaluated][lazy evaluation]_; iteration is _one-way_ and there is no "backing up" to a previous value.
+- They are _consumed_ by iterating over the returned values; there is no resetting or saving in memory.
+- They are not sortable and cannot be reversed.
+- They are not sequence types, and _do not_ have `indexes`. 
+  You cannot reference a previous or future value using addition or subtraction and you cannot use bracket (`[]`) notation or slicing.
+- They cannot be used with the `len()` function, as they have no length.
+- They can be _finite_ or _infinite_ - be careful when collecting all values from an _infinite_ `generator-iterator`!
+
+[iterator]: https://docs.python.org/3.11/glossary.html#term-iterator
+[iterables]: https://wiki.python.org/moin/Iterator
+[lazy evaluation]: https://en.wikipedia.org/wiki/Lazy_evaluation
+~~~~
+
 
 To use the `squares_generator()` generator:
 
@@ -140,7 +164,8 @@ Generators are also very helpful when a process or calculation is _complex_, _ex
 Now whenever `__next__()` is called on the `infinite_sequence` object, it will return the _previous number_ + 1.
 
 
-[generator-iterator]: https://docs.python.org/3.11/glossary.html#term-generator-iterator
+[generator-iterator]: https://docs.python.org/3/glossary.html#term-generator-iterator
+[how-to-iterator]: https://treyhunner.com/2018/06/how-to-make-an-iterator-in-python/#Generators:_the_easy_way_to_make_an_iterator
 [iterables]: https://wiki.python.org/moin/Iterator
 [iterator]: https://docs.python.org/3.11/glossary.html#term-iterator
 [lazy iterator]: https://en.wikipedia.org/wiki/Lazy_evaluation

concepts/unpacking-and-multiple-assignment/about.md

@@ -8,7 +8,7 @@ A very common example of this behavior is `for item in list`, where `item` takes
 This allows for code to be more concise and readable, and is done by separating the variables to be assigned with a comma such as `first, second, third = (1,2,3)` or `for index, item in enumerate(iterable)`.
 
 The special operators `*` and `**` are often used in unpacking contexts.
-`*` can be used to combine multiple `lists`/`tuples` into one `list`/`tuple` by _unpacking_ each into a new common `list`/`tuple`.
+`*` can be used to combine multiple `list`s/`tuple`s into one `list`/`tuple` by _unpacking_ each into a new common `list`/`tuple`.
 `**` can be used to combine multiple dictionaries into one dictionary by _unpacking_ each into a new common `dict`.
 
 When the `*` operator is used without a collection, it _packs_ a number of values into a `list`.
@@ -73,7 +73,7 @@ Since `tuples` are immutable, you can't swap elements in a `tuple`.
 The examples below use `lists` but the same concepts apply to `tuples`.
 ~~~~
 
-In Python, it is possible to [unpack the elements of `list`/`tuple`/`dictionary`][unpacking] into distinct variables.
+In Python, it is possible to [unpack the elements of a `list`/`tuple`/`dict`][unpacking] into distinct variables.
 Since values appear within `lists`/`tuples` in a specific order, they are unpacked into variables in the same order:
 
 ```python
@@ -94,7 +94,7 @@ If there are values that are not needed then you can use `_` to flag them:
 
 ### Deep unpacking
 
-Unpacking and assigning values from a `list`/`tuple` inside of a `list` or `tuple` (_also known as nested lists/tuples_), works in the same way a shallow unpacking does, but often needs qualifiers to clarify the values context or position:
+Unpacking and assigning values from a `list`/`tuple` inside of a `list` or `tuple` (_also known as nested lists/tuples_), works in the same way a shallow unpacking does, but often needs qualifiers to clarify the value's context or position:
 
 ```python
 >>> fruits_vegetables = [["apple", "banana"], ["carrot", "potato"]]

concepts/unpacking-and-multiple-assignment/introduction.md

@@ -8,7 +8,7 @@ A very common example of this behavior is `for item in list`, where `item` takes
 This allows for code to be more concise and readable, and is done by separating the variables to be assigned with a comma such as `first, second, third = (1,2,3)` or `for index, item in enumerate(iterable)`.
 
 The special operators `*` and `**` are often used in unpacking contexts.
-`*` can be used to combine multiple `lists`/`tuples` into one `list`/`tuple` by _unpacking_ each into a new common `list`/`tuple`.
+`*` can be used to combine multiple `list`s/`tuple`s into one `list`/`tuple` by _unpacking_ each into a new common `list`/`tuple`.
 `**` can be used to combine multiple dictionaries into one dictionary by _unpacking_ each into a new common `dict`.
 
 When the `*` operator is used without a collection, it _packs_ a number of values into a `list`.

exercises/concept/plane-tickets/.docs/introduction.md

@@ -1,7 +1,7 @@
 # Generators
 
-A `generator` is a function or expression that returns a special type of [iterator][iterator] called [generator iterator][generator-iterator].
-`Generator-iterators` are [lazy][lazy iterator]: they do not store their `values` in memory, but _generate_ their values when needed.
+A `generator` is a function or expression that returns a special type of [iterator][iterator] called a [`generator iterator`][generator-iterator].
+`Generator-iterator`s are [lazy][lazy iterator]: they do not store their `values` in memory, but _generate_ their values when needed.
 
 A generator function looks like any other function, but contains one or more [yield expressions][yield expression].
 Each `yield` will suspend code execution, saving the current execution state (_including all local variables and try-statements_).
@@ -144,8 +144,6 @@ Now whenever `__next__()` is called on the `infinite_sequence` object, it will r
 
 
 [generator-iterator]: https://docs.python.org/3.11/glossary.html#term-generator-iterator
-[iterables]: https://wiki.python.org/moin/Iterator
 [iterator]: https://docs.python.org/3.11/glossary.html#term-iterator
-[lazy evaluation]: https://en.wikipedia.org/wiki/Lazy_evaluation
 [lazy iterator]: https://en.wikipedia.org/wiki/Lazy_evaluation
 [yield expression]: https://docs.python.org/3.11/reference/expressions.html#yield-expressions