Python Overview

Python is a modern programming language useful in various fields of computer science including teaching, maths, data science, machine learning, so-called artificial intelligence, graphics, desktop application development, and cloud application development.

Language Features

Style Guide

IDLE

Provided with the Python distribution. Generally only used in the early days of teaching Python. Useful for quickly checking Python statement syntax, and for running quick calculations requiring python libraries like Math and Pandas.

Run IDLE from Virtual Environment

(.venv) C:\MyProject> python.exe -m idlelib.idle

PyCharm

Preferred tool by certain tutors for teaching software engineering with Python. Also supports HTML, Jupyter Notebooks, JavaScript, TypeScript and SQL.

Show underlying function code: Right click > Go To > Declarations or Usages (F12)

Strings

C style placeholders

integer_value = 4237
print("Decimal integer %d more text" % integer_value) 
print("Hexadecimal integer %x\n" % integer_value)
print("Hexadecimal integer %X\n" % integer_value)
print("Right justify integer (%8d)" % integer_value)
print("Left justify integer (%-8d)\n" % integer_value)

f-Strings

print(f"Hello {fn} {ln} you are {age} years old!")

Splitting Strings

>>> my_string = "Shannon"
>>> my_letters = list(my_string)
['S', 'h', 'a', 'n', 'n', 'o', 'n']

Tuples

The standard way to create tuples is with round brackets. They can also be created without. They can also be created with a single value.

standard_tuple = (1, 2, 3, 4)
no_brackets_tuple = 5, 6, 7, 8
single_value_tuple = 9,

List Iteration

names = ["Baker", "Patterson", "Greening", 2547, 99.442]
names.append("Brown")
names.insert(0, 'Douglas')
for lcv in range(len(names)):
    print(f'{lcv:4} {names[lcv]:15}')

lcv stands for loop control value.

To use the += operator to add a value to a list, the second value must come from another list

>>> list += number
TypeError: 'int' object is not iterable
>>> list += [number]

List from Range

a_range = range(0, 199, 2)
a_list = list(a_range)

print("Type of a_range:", type(a_range), "\n", a_range)
print("Type of a_list:", type(a_list), "\n", a_list)
for number in a_list:
   print(number, end=" ")

Type Comparision

type(9) is int
type(2.5) is float
type('x') is str
type(u'x') is unicode
type(2+3j) is complex
type(my_tuple) is tuple
variable is None

isinstance( 'x', basestring )
isinstance( u'u', basestring )
isinstance( 9, int )
isinstance( 2.5, float )
isinstance( (2+3j), complex )

Map()

>>> data = ['Shannon', 'Douglas', 'Jordan', 'Ware', 'Baker']
>>> def upper(str):
	return str.upper()
>>> list(map(upper, data))

List Comprehensions

List comprehensions are a powerful feature in Python that allows you to create lists in a concise, readable, and efficient way. They're often used for tasks like filtering, transforming, or combining data. (Ollama 3.1)

>>> # Simple List Comprehension
>>> numbers = range(10)
>>> squares = [x**2 for x in numbers]
>>> # Filtering
>>> even_numbers = [x for x in number_list if x % 2 == 0]
>>> # Nested List Comprehension
>>> people = [[dt, en] for dt in data for en in even_numbers]

Some Important Methods

The Python interpreter has a number of functions and types built into it that are always available: Built-in Functions. Some selected examples are as follows...

print("Hello", "World", sep="_", end="!")
die = random.randrange(1, 7)
integer = int(input("Enter and integer: "))
print("The integer is:", integer, "; the id is:", id(integer), "; the type is:", type(integer))
del my_dictionary["Dict-Key"]
my_list.count(value)
type(my_list)
id(my_list)
dir(statistics)

Python Documentation

>>> import statistics
>>> for element in dir(statistics):
	print("="*20, "\n", element, "\n")
	print(eval(f"statistics.{element}.__doc__"), "\n")
:0)