Why Python?

Its features make it an excellent choice for beginners

• Gets things done... your time is valuabe
• Among the most popular programming languages worldwide
  • TIOBE Index
  • Stack Overflow Dev. Survey 2023
• Highly popular in Open Source Projects
• Ever increasing popularity (Google Trends)

Python's Advantages

• Python compares favorable in terms of development time
• Easy to learn
• Simple and elegant syntax
• Open Source
• Multi paradigm scripting/ programming language
• Platform independent
• Excellent tools
• Batteries included
• Easily extensible - lots of third party modules
• Huge community

Python's Disadvantages

• Execution speed
• Block delimiters confusing if editor is not properly configured
• Limited application on mobile platforms

Jobs

• Python Job Board
• Careerjet

• Variable, Assignment
• Comment
• Standard input, standard output and standard error
• Source formatting/ indentation
• Branching
• Loops

• Operator
  • A symbol representing an operation (eg.: mathematical operation)
  • There are arithmetic, logical, assignment, ... operators
• Operator precedence
  • When in doubt, use parenthesis.
  • In order to make your code more readable, use parenthesis

Python code can be executed in a shell by typing python $FILENAME

#!/usr/bin/env python3

"""
A 'Hello world!' program written in Python.
"""

print('Hello, World!')

Python offers it's own read–eval–print loop (REPL), the Python shell
Python commands are immediately executed

Allows to execute different commands based on provided conditions

if <assignment_expression>:
    <suite>
(elif <assignment_expression>: <suite>)*
[else: <suite>]

Example (if)

#!/usr/bin/env python3

LANG = 'en'
# ...
if LANG == 'en':
    output = 'Good Morning!'
elif LANG == 'de':
    output = 'Guten Morgen!'
else:
    output = 'Bonjour!'
print(output)

Visualize execution

Conditional expression

<expression1> if <condition> else <expression2>

#!/usr/bin/env python3

LANG = 'en'
# ...
output = "Good Morning!" if LANG == 'en' else "Guten Morgen!"
print(output)

Structural Pattern Matching

Since Python 3.10 (PEP 634 )

match subject:
    case <pattern_1>:
        <action_1>
    case <pattern_2>:
        <action_2>
    case <pattern_3>:
        <action_3>
    case _:
        <action_wildcard>

Example (match)

#!/usr/bin/env python3

LANG = 'en'
# ...
match LANG:
    case 'en':
        output = 'Good Morning!'
    case 'de':
        output = 'Guten Morgen!'
    case _:
        output = 'Bonjour!'
print(output)

Visualize execution

Exceptions

Allow splitting up error detection and error handling

try:
    <suite>
(except [<expression> [as <identifier>]]: <suite>)+
[else: <suite>]
[finally: <suite>]

Example (try)

#!/usr/bin/env python3

length = 3
rectangle_area = 12
# ...
try:
    width = rectangle_area / length
except ZeroDivisionError:
    print("The length of a rectangle must not be 0")
    # deal with problem or re-raise the exception
    raise
print(width)

Visualize execution

Python 3 Video Tutorial - Basic Control Flow

...is used for repeated execution as long as an expression is true

while <assignment_expression>:
    <suite>  # may include `break` and `continue`
[else: <suite>]

Example

#!/usr/bin/env python3

amount = 3000  # initial investment in euro
GOAL = 4000
INTEREST = 0.03  # 3%

years = 0
while amount < GOAL:
    years += 1
    amount = amount * (1 + INTEREST)

print(f"you'll reach your investment goal after {years} years")

Visualize execution

Python 3 Video Tutorial - While Loops