functions

https://docs.python.org/3/library/functions.html

calling

def my_function():

  value = 100

  print(f"My value is: {value}")

my_function()

passing

def my_function(my_argument):

  print(f"The text is: {my_argument}")

my_function("my_ text")

return

def my_function(my_argument):

   my_argument += 1

   return my_argument

a docstring describes a function viz. they are the function's documentation

docstrings are displayed with calling help()

function.__doc__ #gives the docstring directly

syntax example

def clean_string(text):

  """This functions cleans text inputs."""

  no_spaces = text.replace(" ", "_")

  clean_text = no_spaces.lower()

  return clean_text

the data structure viz. value that is passed inside a function

positional argument

separated by a comma

arbitrary positional argument

* #creates an arbitrary positional argument i.e. unlimited input quantity of arguments

def my_function(*args): #*args is the typical variable name for arbitrary positional argument

keyword argument

keyword = value

arbitrary keyword argument

** #creates an arbitrary keyword argument i.e. unlimited input quantity of arguments

def my_function(**kwargs): #*kwargs is the typical variable name for arbitrary keyword argument

help

help(function) #gives the arguments of a function etc.

lambda #creates an anonymos function

use lambda only for a simple task that happens only once

syntax

lambda argument: expression #x is often use for a single argument

examples

(lambda x: sum(x) / len(x))[3, 4, 5] #calculates the average of 3, 4, 5

(lambda x, y: x ** y)(3, 2) #caclulates 3²

average = lambda x: sum(x) / len(x) #stores the lambda funtions in a variable that can be called

upper_case = list(map(lambda x: x.upper(), name_list)) #turns name_list into upper cases

def clean_string(text):

  no_spaces = text.replace(" ", "_")

  clean_text = no_spaces.lower()

  return clean_text

converted_text = clean_string("WronG CAsE iNpUt!")

print(converted_text)

def convert_data_structure(data, data_type="list"): #preset an argument

  if data_type == "tuple":

    data = tuple(data)

  elif data_type == "set":

    data = set(data)

  else:

    data = list(data)

  return data

convert_data_structure({"a", 1, "b", 2, "c", 3}, data_type="set") #if no data type were give, it would ouput a list

def concat(*args):

  result = ""

  for arg in args:

    result += " " + arg

  return result

print(concat("My", "concatenated", "output!"))

def concat(**kwargs):

  result = ""

  for kwarg in kwargs.values():

    result += " " + kwarg

  return result

print(concat(start="Python", middle="is", end="great!"))