Python introduction

What is Python?

Collections of functionalities
Cover a certain topic / domain
Everybody can share a library
- Many domains covered
- Not verified and not always correct
~ 300,000 packages

Lists — mutable, ordered
- my_list = [1, ‘test’, 5.8]
Tuples — immutable, ordered
- my_tuple = (1, ‘test’, 5.8)
Dictionaries — key-value pairs, no order
- my_dict = {‘petra’ : ’petra@adaltas.com’}
Sets — mutable, unordered, no repeats
- my_set = {1, 3, 6, 9}

Click here to explore more functionalities of Python collections.

Through functions:

Code that solves a specific task
Types:
- Built-in: type(), `print()“
- Imported from libraries: from <module> import <function>
- Custom: def my_funct()

To be able to write meaningful functions, we need to get to know some other constructs first:

Evaluates a condition and depending on the result, it executes different branch of code:

a = 200
b = 33

if b > a:
  print("b is greater than a")
else:
  print("b is not greater than a")

If you want multiple conditions, you can chain them with elif.

To repeat the same action multiple times, you use loops:

for i in range(1, 10):
  print(i)

i = 0

while i < 10:
  print(i)
  i = i + 1

Expressions that compares data and returns a Boolean value as a result (True, False):

When a function we need doesn’t exist, we need to write it ourselves. In Python:

It always starts with def
It can take none, one or more arguments
It always returns a value
- explicit return: a function contains return statement
- implicit return: a function doesn’t contains return statement. In this case, the function returns None.

# This function returns name
def return_name(name):
  return(name)

# This function prints name and returns None
def print_name(name):
  print(name)