Tiny Python Projects

Tiny Python Projects
brief contents
contents
preface
Why write Python?
Why did I write this book?
acknowledgments
about this book
Who should read this book
How this book is organized: A roadmap
About the code
Software/hardware requirements
iiveBook discussion forum
Other online resources
about the author
about the cover
Getting started: Introduction and installation guide
Writing command-line programs
Using test-driven development
Setting up your environment
Code examples
Getting the code
Installing modules
Code formatters
Code linters
How to start writing new programs
Why not Notebooks?
The scope of topics we’ll cover
Why not object-oriented programming?
A note about the lingo
1 How to write and test a Python program
1.1 Creating your first program
1.2 Comment lines
1.3 Testing your program
1.4 Adding the #! (shebang) line
1.5 Making a program executable
1.6 Understanding $PATH
1.6.1 Altering your $PATH
1.7 Adding a parameter and help
1.8 Making the argument optional
1.9 Running our tests
1.10 Adding the main() function
1.11 Adding the get_args() function
1.11.1 Checking style and errors
1.12 Testing hello.py
1.13 Starting a new program with new.py
1.14 Using template.py as an alternative to new.py
Summary
2 The crow’s nest: Working with strings
2.1 Getting started
2.1.1 How to use the tests
2.1.2 Creating programs with new.py
2.1.3 Write, test, repeat
2.1.4 Defining your arguments
2.1.5 Concatenating strings
2.1.6 Variable types
2.1.7 Getting just part of a string
2.1.8 Finding help in the REPL
2.1.9 String methods
2.1.10 String comparisons
2.1.11 Conditional branching
2.1.12 String formatting
2.1.13 Time to write
2.2 Solution
2.3 Discussion
2.3.1 Defining the arguments with get_args()
2.3.2 The main() thing
2.3.3 Classifying the first character of a word
2.3.4 Printing the results
2.3.5 Running the test suite
2.4 Going further
Summary
3 Going on a picnic: Working with lists
3.1 Starting the program
3.2 Writing picnic.py
3.3 Introducing lists
3.3.1 Adding one element to a list
3.3.2 Adding many elements to a list
3.3.3 Indexing lists
3.3.4 Slicing lists
3.3.5 Finding elements in a list
3.3.6 Removing elements from a list
3.3.7 Sorting and reversing a list
3.3.8 Lists are mutable
3.3.9 Joining a list
3.4 Conditional branching with if/elif/else
3.4.1 Time to write
3.5 Solution
3.6 Discussion
3.6.1 Defining the arguments
3.6.2 Assigning and sorting the items
3.6.3 Formatting the items
3.6.4 Printing the items
3.7 Going further
Summary
4 Jump the Five: Working with dictionaries
4.1 Dictionaries
4.1.1 Creating a dictionary
4.1.2 Accessing dictionary values
4.1.3 Other dictionary methods
4.2 Writing jump.py
4.3 Solution
4.4 Discussion
4.4.1 Defining the parameters
4.4.2 Using a dict for encoding
4.4.3 Various ways to process items in a series
4.4.4 (Not) using str.replace()
4.5 Going further
Summary
5 Howler: Working with files and STDOUT
5.1 Reading files
5.2 Writing files
5.3 Writing howler.py
5.4 Solution
5.5 Discussion
5.5.1 Defining the arguments
5.5.2 Reading input from a file or the command line
5.5.3 Choosing the output file handle
5.5.4 Printing the output
5.5.5 A low-memory version
5.6 Going further
Summary
6 Words count: Reading files and STDIN, iterating lists, formatting strings
6.1 Writing wc.py
6.1.1 Defining file inputs
6.1.2 Iterating lists
6.1.3 What you’re counting
6.1.4 Formatting your results
6.2 Solution
6.3 Discussion
6.3.1 Defining the arguments
6.3.2 Reading a file using a for loop
6.4 Going further
Summary
7 Gashlycrumb: Looking items up in a dictionary
7.1 Writing gashlycrumb.py
7.2 Solution
7.3 Discussion
7.3.1 Handling the arguments
7.3.2 Reading the input file
7.3.3 Using a dictionary comprehension
7.3.4 Dictionary lookups
7.4 Going further
Summary
8 Apples and Bananas: Find and replace
8.1 Altering strings
8.1.1 Using the str.replace() method
8.1.2 Using str.translate()
8.1.3 Other ways to mutate strings
8.2 Solution
8.3 Discussion
8.3.1 Defining the parameters
8.3.2 Eight ways to replace the vowels
8.4 Refactoring with tests
8.5 Going further
Summary
9 Dial-a-Curse: Generating random insults from lists of words
9.1 Writing abuse.py
9.1.1 Validating arguments
9.1.2 Importing and seeding the random module
9.1.3 Defining the adjectives and nouns
9.1.4 Taking random samples and choices
9.1.5 Formatting the output
9.2 Solution
9.3 Discussion
9.3.1 Defining the arguments
9.3.2 Using parser.error()
9.3.3 Program exit values and STDERR
9.3.4 Controlling randomness with random.seed()
9.3.5 Iterating with range() and using throwaway variables
9.3.6 Constructing the insults
9.4 Going further
Summary
10 Telephone: Randomly mutating strings
10.1 Writing telephone.py
10.1.1 Calculating the number of mutations
10.1.2 The mutation space
10.1.3 Selecting the characters to mutate
10.1.4 Mutating a string
10.1.5 Time to write
10.2 Solution
10.3 Discussion
10.3.1 Mutating a string
10.3.2 Using a list instead of a str
10.4 Going further
Summary
11 Bottles of Beer Song: Writing and testing functions
11.1 Writing bottles.py
11.1.1 Counting down
11.1.2 Writing a function
11.1.3 Writing a test for verse()
11.1.4 Using the verse() function
11.2 Solution
11.3 Discussion
11.3.1 Counting down
11.3.2 Test-driven development
11.3.3 The verse() function
11.3.4 Iterating through the verses
11.3.5 1,500 other solutions
11.4 Going further
Summary
12 Ransom: Randomly capitalizing text
12.1 Writing ransom.py
12.1.1 Mutating the text
12.1.2 Flipping a coin
12.1.3 Creating a new string
12.2 Solution
12.3 Discussion
12.3.1 Iterating through elements in a sequence
12.3.2 Writing a function to choose the letter
12.3.3 Another way to write list.append()
12.3.4 Using a str instead of a list
12.3.5 Using a list comprehension
12.3.6 Using a map() function
12.4 Comparing methods
12.5 Going further
Summary
13 Twelve Days of Christmas: Algorithm design
13.1 Writing twelve_days.py
13.1.1 Counting
13.1.2 Creating the ordinal value
13.1.3 Making the verses
13.1.4 Using the verse() function
13.1.5 Printing
13.1.6 Time to write
13.2 Solution
13.3 Discussion
13.3.1 Making one verse
13.3.2 Generating the verses
13.3.3 Printing the verses
13.4 Going further
Summary
14 Rhymer: Using regular expressions to create rhyming words
14.1 Writing rhymer.py
14.1.1 Breaking a word
14.1.2 Using regular expressions
14.1.3 Using capture groups
14.1.4 Truthiness
14.1.5 Creating the output
14.2 Solution
14.3 Discussion
14.3.1 Stemming a word
14.3.2 Formatting and commenting the regular expression
14.3.3 Using the stemmer() function outside your program
14.3.4 Creating rhyming strings
14.3.5 Writing stemmer() without regular expressions
14.4 Going further
Summary
15 The Kentucky Friar: More regular expressions
15.1 Writing friar.py
15.1.1 Splitting text using regular expressions
15.1.2 Shorthand classes
15.1.3 Negated shorthand classes
15.1.4 Using re.split() with a captured regex
15.1.5 Writing the fry() function
15.1.6 Using the fry() function
15.2 Solution
15.3 Discussion
15.3.1 Writing the fry() function manually
15.3.2 Writing the fry() function with regular expressions
15.4 Going further
Summary
16 The scrambler: Randomly reordering the middles of words
16.1 Writing scrambler.py
16.1.1 Breaking the text into lines and words
16.1.2 Capturing, non-capturing, and optional groups
16.1.3 Compiling a regex
16.1.4 Scrambling a word
16.1.5 Scrambling all the words
16.2 Solution
16.3 Discussion
16.3.1 Processing the text
16.3.2 Scrambling a word
16.4 Going further
Summary
17 Mad Libs: Using regular expressions
17.1 Writing mad.py
17.1.1 Using regular expressions to find the pointy bits
17.1.2 Halting and printing errors
17.1.3 Getting the values
17.1.4 Substituting the text
17.2 Solution
17.3 Discussion
17.3.1 Substituting with regular expressions
17.3.2 Finding the placeholders without regular expressions
17.4 Going further
Summary
18 Gematria: Numeric encoding of text using ASCII values
18.1 Writing gematria.py
18.1.1 Cleaning a word
18.1.2 Ordinal character values and ranges
18.1.3 Summing and reducing
18.1.4 Using functools.reduce
18.1.5 Encoding the words
18.1.6 Breaking the text
18.2 Solution
18.3 Discussion
18.3.1 Writing word2num()
18.3.2 Sorting
18.3.3 Testing
18.4 Going further
Summary
19 Workout of the Day: Parsing CSV files, creating text table output
19.1 Writing wod.py
19.1.1 Reading delimited text files
19.1.2 Manually reading a CSV file
19.1.3 Parsing with the csv module
19.1.4 Creating a function to read a CSV file
19.1.5 Selecting the exercises
19.1.6 Formatting the output
19.1.7 Handling bad data
19.1.8 Time to write
19.2 Solution
19.3 Discussion
19.3.1 Reading a CSV file
19.3.2 Potential runtime errors
19.3.3 Using pandas.read_csv() to parse the file
19.3.4 Formatting the table
19.4 Going further
Summary
20 Password strength: Generating a secure and memorable password
20.1 Writing password.py
20.1.1 Creating a unique list of words
20.1.2 Cleaning the text
20.1.3 Using a set
20.1.4 Filtering the words
20.1.5 Titlecasing the words
20.1.6 Sampling and making a password
20.1.7 l33t-ify
20.1.8 Putting it all together
20.2 Solution
20.3 Discussion
20.3.1 Cleaning the text
20.3.2 A king’s ransom
20.3.3 How to l33t()
20.3.4 Processing the files
20.3.5 Sampling and creating the passwords
20.4 Going further
Summary
21 Tic-Tac-Toe: Exploring state
21.1 Writing tictactoe.py
21.1.1 Validating user input
21.1.2 Altering the board
21.1.3 Printing the board
21.1.4 Determining a winner
21.2 Solution
21.2.1 Validating the arguments and mutating the board
21.2.2 Formatting the board
21.2.3 Finding the winner
21.3 Going further
Summary
22 Tic-Tac-Toe redux: An interactive version with type hints
22.1 Writing itictactoe.py
22.1.1 Tuple talk
22.1.2 Named tuples
22.1.3 Adding type hints
22.1.4 Type verification with Mypy
22.1.5 Updating immutable structures
22.1.6 Adding type hints to function definitions
22.2 Solution
22.2.1 A version using TypedDict
22.2.2 Thinking about state
22.3 Going further
Summary
Epilogue
Appendix—Using argparse
A.1 Types of arguments
A.2 Using a template to start a program
A.3 Using argparse
A.3.1 Creating the parser
A.3.2 Creating a positional parameter
A.3.3 Creating an optional string parameter
A.3.4 Creating an optional numeric parameter
A.3.5 Creating an optional file parameter
A.3.6 Creating a flag option
A.3.7 Returning from get_args
A.4 Examples using argparse
A.4.1 A single positional argument
A.4.2 Two different positional arguments
A.4.3 Restricting values using the choices option
A.4.4 Two of the same positional arguments
A.4.5 One or more of the same positional arguments
A.4.6 File arguments
A.4.7 Manually checking arguments
A.4.8 Automatic help
Summary
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