Python Basic and Advanced (22.3.2021 - 25.3.2021)¶

Agenda ¶

Day 1: Programming Basics
- Variables
- Control Flow: if, while, for
- Functions
- Exercises
Day 2: Python, Advanced
- Data Structures: list, set, dict
- Iteration
- File I/O (CSV Files?)
- Exercises
Day 3: even more advanced
- Object Oriented Programming
- Unit Testing
- Decorators
- Exercises
Day 4: Consulting

Log ¶

We’re lagging behind what’s in the agenda, don’t want to lose anybody.

Day 1 ¶

Basics from the slides, up until if (see here)

Exercise: Determine Maximum of Two Numbers

Solution, doing everything by hand …

code/maximum-potschert.py¶

import sys


left = int(sys.argv[1])
right = int(sys.argv[2])

if left < right:
    print(right)
else:
    print(left)

Solution, knowing about the map() function and the max() function

code/maximum-gscheit.py¶

import sys

print(max(map(int, sys.argv[1:])))

Day 2 ¶

Exercise: digit translation

code/digit.py¶

import sys

lookup_table = {
    0: 'zero',
    1: 'one',
    2: 'two',
    3: 'three',
    4: 'four',
    5: 'five',
    6: 'six',
    7: 'seven',
    8: 'eight',
    9: 'nine',
}

if len(sys.argv) != 2:
    print('gib eine parameter an  mich, depp!', file=sys.stderr)
    sys.exit(1)

digit = int(sys.argv[1])

word = lookup_table.get(digit)
if word == None:
    print('nix drin', file=sys.stderr)
    sys.exit(3)
else:
    print(word)

while

Exercise: primeness (using while)

code/prime-while.py¶

import sys


number = int(sys.argv[1])

if number == 1:
    print(number, 'is not prime')
    sys.exit(0)

divisor = 2

while divisor < number:
    if number % divisor == 0:
        print(number, 'is not prime')
        break

    divisor += 1
else:
    print(number, 'is prime')

for, range()

Exercise: primeness (using for)

code/prime-for.py¶

import sys


number = int(sys.argv[1])

if number == 1:
    print(number, 'is not prime')
    sys.exit(0)

for divisor in range(2, number):
    if number % divisor == 0:
        print(number, 'is not prime')
        break
else:
    print(number, 'is prime')

Functions

Exercise: primeness (function)

code/prime-function.py¶

import sys

def is_prime(number):
    if number == 1:
        return False
    
    for divisor in range(2, number):
        if number % divisor == 0:
            return False
    else:
        return True

n = int(sys.argv[1])
if is_prime(n):
    print(n, 'is prime')
else:
    print(n, 'is not prime')
    

Exercise: uniq function

code/uniq.py¶

def uniq(seq):
    have = set()
    ret_l = []
    for element in seq:
        if element not in have:
            ret_l.append(element)
            have.add(element)
    return ret_l

l = [4, 2, 4, 5, 6, 7, 8, 4, 2, 8, 9]

uniq_l = uniq(l)

for i in uniq_l:
    print(i)

# 4
# 2
# 5
# 6
# 7
# 8
# 9

Large group exercise (extending until course finish). Something with CSV files. File IO for a purpose.

Day 3 ¶

Cold start in the morning:

uniq() transformed into generator
with
is

Continue with the group exercise. Moved the code over to Github last evening, starting with a short Git intro.

Using csv.DictReader; see here
Group exercise on Github

Day 4 ¶

Use collections.namedtuple for our dict objects that we use as records.
Test driven development
OO
MQTT

Links ¶

Python/NumPy course by myself, including links
SciPy: Interpolation
Pandas: read_excel(). Makes sense to look into: the converters parameter, for example, looks like it would offer a cool opportunity to hook in our dumb str("123,456") (note the comma) -> float(123.456) conversions.
Virtual Environments, and Python Package Index (PyPI)

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