1. Print output to console

Ndamulelo Nemakhavhani

Jan 15, 2019·2 min read

>> print(Python is the best!')

2. Common data types

Numbers

• Integers e.g. 5
• Floats e.g. 5.431
• Complex numbers e.g. 1 + 3j

Strings

• “Á string is a sequence of characters’’

Each of these data types support a number of common operations:

>>> 'hello' * 3 # output: hellohellohello>>> 'hello' + 3 # Error>>> 'hello' + str(3) # hello3>>> 8 / 1 # 8.0>>> 8 // 1 # 8>>> 8 // 1.0 # 8.0>>> 1 + 3j.real # 1.0

3. Abstract data types — data model defined by behavior

List

• Collection of ordered items e.g. [ ‘USA’, ‘UK’, ‘RSA’]
• Members can be any valid python data types

Set

• Can only contain unique item e.g. [ 1,5,2]

Tuples

• Cannot be changed once initialized e.g. (4,3)

Dictionary or hasmap

• Store data as key:value pairs
• e.g. { ‘ndamu’: 098 221 2314 }

4. String formatting

• Used to populate placeholders with actual values during code execution.

>>> print('Her name is %s. She is %d years old' %('lili', 3))   # Her name is lili. She is 3 years old

• % s — Strings or objects that can be represented as strings
• %d — Integers or non-decimal numbers e.g. 7
• %.<x>f — Floating point number with x number of digits after the dot
• %x — Hexadecimal numbers

5. Classes

• Define the characteristics and behavior of objects

class Vehicle:
  def __init__(self, name, make, year=2019):
      name = self.name
      make = self.make
      year = self.year  def accelerate:
      print('Increasing speed')# Instantiate car object
>>> bmw = Vehicle('BMW', 'M6', 2012)>>> print( bmw.make )
    # M6

6. Modules and packages

• Any python file with a dedicated function is module , e.g. draw.py
• A module or part of a module can be imported to a project using the following syntax

>>> import draw>>> from draw import draw_polygon

• A collection of modules in a directory is called a package.
• This directory must contain a file called __init__.py for python to treat it as a module.