Fix miscellaneous typos and spelling mistakes

Author: olegresearcher

data/part-10/1-class-hierarchies.md

@@ -307,7 +307,7 @@ class PlatinumCard(BonusCard):
         return bonus
 ```
 
-So, the bonus for a PlatinumCard is calculated by calling the overriden method in the base class, and then adding an extra 5 percent to the base result. An example of how these classes are used:
+So, the bonus for a PlatinumCard is calculated by calling the overridden method in the base class, and then adding an extra 5 percent to the base result. An example of how these classes are used:
 
 ```python
 if __name__ == "__main__":

data/part-10/4-application-development.md

@@ -26,7 +26,7 @@ Objects and classes are by no means necessary in every programming context. For
 
 When programs grow in complexity, the amount of details quickly becomes unmanageable, unless the program is organised in some systematic way. Even some of the more complicated exercises on this course so far would have benefited from the examples set in this part of the material.
 
-Fo decades the concept of [separation of concerns](https://en.wikipedia.org/wiki/Separation_of_concerns) has been one of the central principles in programming, and the larger field of computer science. Quoting from Wikipedia:
+For decades the concept of [separation of concerns](https://en.wikipedia.org/wiki/Separation_of_concerns) has been one of the central principles in programming, and the larger field of computer science. Quoting from Wikipedia:
 
 _Separation of concerns is a design principle for separating a computer program into distinct sections such that each section addresses a separate concern. A concern is a set of information that affects the code of a computer program._
 
@@ -147,7 +147,7 @@ application = PhoneBookApplication()
 application.execute()
 ```
 
-This program doesn't do very much yet, but let's go through the contents. The constructor method creates a new PhoneBook, which is stored in a private attribute. The method `execute(self)` starts the program's text-based user interface, the core of which is the `while` loop, which keeps asking the user for commands until they type in the command for exiting. There is also a method for intructions, `help(self)`, which is called before entering the loop, so that the instructions are printed out.
+This program doesn't do very much yet, but let's go through the contents. The constructor method creates a new PhoneBook, which is stored in a private attribute. The method `execute(self)` starts the program's text-based user interface, the core of which is the `while` loop, which keeps asking the user for commands until they type in the command for exiting. There is also a method for instructions, `help(self)`, which is called before entering the loop, so that the instructions are printed out.
 
 Now, let's add some actual functionality. First, we implement adding new data to the phone book:
 
@@ -680,7 +680,7 @@ The file handling process in the PhoneBook application proceeds as follows: the
 There are many good guidebooks for learning about good programming practices. One such is [Clean Code](https://www.amazon.com/Clean-Code-Handbook-Software-Craftsmanship/dp/0132350882) by Robert Martin. The code examples in the book are implemented in Java, however, so working through the examples can be quite cumbersome at this point in your programming career, although the book itself is much recommended by the course staff. The themes of easily maintained, expandable, good quality code will be further explored on the courses
 [Software Development Methods](https://studies.helsinki.fi/courses/cu/hy-CU-118024742-2020-08-01) and [Software Engineering](https://studies.helsinki.fi/courses/cu/hy-CU-118024909-2020-08-01).
 
-Writing code according to established object oriented programming principles comes at a price. You will likely end up writing more code than you would, were you to write your implementation in one continuous bout of spaghetti code. One of the key skills of a porgrammer is to decide the best approach for each situation. Sometimes it is necessary to just hack something together quickly for immediate use. On the other hand, if in the foreseeable future it can be expected that the code will be reused, maintained or futher developed, either by you or, more critically, by someone else entirely, the readability and logical modularity of the program code become essential. More often than not, if it is worth doing, it is worth doing well, even in the very early stages of development.
+Writing code according to established object oriented programming principles comes at a price. You will likely end up writing more code than you would, were you to write your implementation in one continuous bout of spaghetti code. One of the key skills of a programmer is to decide the best approach for each situation. Sometimes it is necessary to just hack something together quickly for immediate use. On the other hand, if in the foreseeable future it can be expected that the code will be reused, maintained or further developed, either by you or, more critically, by someone else entirely, the readability and logical modularity of the program code become essential. More often than not, if it is worth doing, it is worth doing well, even in the very early stages of development.
 
 To finish off this part of the material you will implement one more larger application.
 

data/part-11/1-list-comprehensions.md

@@ -38,7 +38,7 @@ numbers = [1, 2, 3, 6, 5, 4, 7]
 strings = [str(number) for number in numbers]
 ```
 
-The second line above contains many of the same elements as the more traditional iterative apporach, but the syntax is different. One way of generalising a list comprehension statement would be
+The second line above contains many of the same elements as the more traditional iterative approach, but the syntax is different. One way of generalising a list comprehension statement would be
 
 `[<expression> for <item> in <series>]`
 
@@ -107,7 +107,7 @@ if __name__ == "__main__":
     print(factorials)
 ```
 
-List comprehensions allow us to express the same functionality more consisely, usually without losing any of the readability.
+List comprehensions allow us to express the same functionality more concisely, usually without losing any of the readability.
 
 We can also return a list comprehension statement from a function directly. If we needed a function for producing factorials for lists of numbers, we could achieve it very concisely:
 

data/part-11/2-more-comprehensions.md

@@ -443,7 +443,7 @@ When the function is called with the arguments `most_common_words("comprehension
 
 </sample-output>
 
-NB: the case of letters affects the results, and all inflected forms are unique words in this exercise. That is, the words `List`, `lists` and `list` are each separate words here, and only `list` has enough occurrences to make it to the returned list. All punctutation should be removed before counting up the occurrences.
+NB: the case of letters affects the results, and all inflected forms are unique words in this exercise. That is, the words `List`, `lists` and `list` are each separate words here, and only `list` has enough occurrences to make it to the returned list. All punctuation should be removed before counting up the occurrences.
 
 It is up to you to decide how to implement this. The easiest way would likely be to make use of list and dictionary comprehensions.
 

data/part-11/3-recursion.md

@@ -146,7 +146,7 @@ The factorial of 6 is 720
 
 If the parameter of the recursive factorial function is 0 or 1, the function returns 1, because this is how the factorial operation is defined. In any other case the function returns the value `n * factorial(n - 1)`, which is the value of its parameter `n` multiplied by the return value of the function call `factorial(n - 1)`.
 
-The crucial part here is that the function definition contains a stop condition. If this is met, the recursion ends. In this case that condition is `n < 2`. We know it will be reached eventually, beacuse the value passed as the argument to the function is decreased by one on each level of the recursion.
+The crucial part here is that the function definition contains a stop condition. If this is met, the recursion ends. In this case that condition is `n < 2`. We know it will be reached eventually, because the value passed as the argument to the function is decreased by one on each level of the recursion.
 
 The [visualisation tool](http://www.pythontutor.com/visualize.html#mode=edit) can be a great help in making sense of recursive programs.
 

data/part-11/4-more-recursion-examples.md

@@ -459,7 +459,7 @@ The first exercise point is granted for a working application when all user inpu
 
 ## Handling errors in user input
 
-To gain the second exercise point for this exercise your application is expected to recover from erroneus user input. Any input which does not follow the specified format should produce an error message _erroneous input_, and result in yet another repeat of the loop asking for a new command:
+To gain the second exercise point for this exercise your application is expected to recover from erroneous user input. Any input which does not follow the specified format should produce an error message _erroneous input_, and result in yet another repeat of the loop asking for a new command:
 
 <sample-output>
 

data/part-12/2-generators.md

@@ -249,7 +249,7 @@ jkl
 
 Please write a function named `word_generator(characters: str, length: int, amount: int)` which returns a new generator for generating random words based on the parameters given.
 
-A random word is generated by selecting from the string named `characters` as many characters as is indicated by the argument `length`. The same character can appear many times in a random word.
+A random word is generated by selecting from the string named `characters` as many characters as indicated by the argument `length`. The same character can appear many times in a random word.
 
 The generator returns as many words as specified by the argument `amount` before terminating.
 

data/part-12/3-functional-programming.md

@@ -650,7 +650,7 @@ If the initial value is left out, `reduce` takes the first item in the list as t
 
 </text-box>
 
-**NB:** if the items in the series are of a different type than the intended reduced result, the thrd argument is mandatory. The example with the bank accounts would not work without the initial value. That is, trying this
+**NB:** if the items in the series are of a different type than the intended reduced result, the third argument is mandatory. The example with the bank accounts would not work without the initial value. That is, trying this
 
 ```python
 balances_total = reduce(balance_sum_helper, accounts)

data/part-4/4-definite-iteration.md

@@ -176,7 +176,7 @@ for i in range(1, 9, 2):
 
 </sample-output>
 
-A step can also be negative. Then the range will be in reversed orded. Notice the first two arguments are also flipped here:
+A step can also be negative. Then the range will be in reversed order. Notice the first two arguments are also flipped here:
 
 ```python
 for i in range(6, 2, -1):

data/part-5/1-more-lists.md

@@ -300,7 +300,7 @@ Alan: age 39 years, height 1.78 meters
 
 The `for` loop goes through the items in the outer list one by one. That is, each list containing information about a single person is, in turn, assigned to the variable `person`.
 
-Lists arent always the best way to present data, such as information about a person. We will soon come across Python _dictionaries_, which are often better suited to such situations.
+Lists aren't always the best way to present data, such as information about a person. We will soon come across Python _dictionaries_, which are often better suited to such situations.
 
 ## Matrices
 
@@ -333,7 +333,7 @@ print(my_matrix)
 
 </sample-output>
 
-Like any other list, the rows of the matrix can be traversed wth a `for` loop. The following code prints out each row of the matrix on a separate line:
+Like any other list, the rows of the matrix can be traversed with a `for` loop. The following code prints out each row of the matrix on a separate line:
 
 ```python
 my_matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]