Introduction to Python Programming Basics(Part 1)

Variables

A variable is a container for a value and it can be of various data types.

Variable Rules

• Variable names are case sensitive
• Variable names must start with a letter or underscore
• Variables can have numbers but cannot start with numbers

Data Types 

int —  for numericals

string — for alphanumericals

float — for numerics with decimal points

boolean — true or false 

	x = 1 #int
	y = 1.22 #float
	name = "Billy" #string
	is_cool = True #boolean
	#x, y, name, is_cool = (1, 1.22, "Billy", True)
	print(x, y, name, is_cool)

view raw Variables.py hosted with ❤ by GitHub

Strings

Strings in python can be written with either single or double quotes 

Lists

A list is a collection which is ordered and can be changed.

A list also allows duplicate members.

To create a list we usually use square brackets or we can use a constructor as shown below;

	numbers = [1, 2, 3, 4, 5]
	names = ["Billy", "Dan"]
	#Get a value from list
	print(numbers[2])
	#Append to list
	names.append("Okeyo")
	print(names)
	#Removing from list
	numbers.remove(5)
	print(numbers)
	#Insert at specific position
	numbers.insert(3, 10)
	print(numbers)
	#Remove with pop
	numbers.pop(3)
	print(numbers)
	#reverse list
	names.reverse()
	print(names)
	#Adding a duplicate
	names.insert(2, "Dan")
	print(names)

view raw Lists.py hosted with ❤ by GitHub

Tuples

A tuple is a collection which is ordered and cannot be changed.

A tuple also allows duplicate members.

In creating tuples we use parenthesis

	numbers = (1, 2, 3, 4, 5)
	names = ("Billy", "Dan")
	print(type(names))
	#When declaring one value in a tuple you should add a comma after it
	campus = ("Thika")
	print(type(campus))
	campus = ("Thika",)
	print(type(campus))
	#Let's try changing a Value
	#names[0] = "Okeyo"
	#deleting a tuple
	#del numbers
	#print(numbers)

view raw Tuples.py hosted with ❤ by GitHub

Sets

A set is a collection which is unordered and unindexed which means when I print a set now it won’t be in the same when i print it again.

A set doesn’t allow duplicate members

	names = {"Billy", "Dan"}
	print(names)
	#Check if a value is in a set
	print("Billy" in names)
	#Add to set
	names.add("Okeyo")
	print(names)
	#Remove from set
	names.remove("Dan")
	print(names)
	#Clearing a set
	#names.clear()
	#print(names)
	#Let's try adding a duplicate
	names.add("Billy")
	print(names)

view raw Sets.py hosted with ❤ by GitHub

Dictionaries 

A dictionary is a collection which is unordered, indexed and changeable.

A dictionary doesn’t allow duplicate members.

	# A dictionary is unordered collection, changeable and indexed, it doesn't allow duplicate members
	student = {
	"Name": "Billy",
	"Reg No": "BIT/001",
	"Age": 50
	}
	print(type(student), student)
	# Get a Value from dictionaries
	print(student["Name"])
	print(student.get("Reg No"))
	# Adding values
	student["Course"] = "BIT"
	print(student)
	# Getting Dictionary Keys
	print(student.keys())
	# Coping a Dictionary
	student1 = student.copy()
	student1["Year"] = "2020"
	print(student1)
	# Dictionary List
	lecturers = [
	{"Name": "John", "Age": 50},
	{"Name": "Doe", "Age": 30}
	]

view raw Dictionary.py hosted with ❤ by GitHub

Functions

A function is a block of code which executes upon calling 

Python is very sensitive to indentions and thus in creating functions, we make use of indents.

In creating functions we use the def keyword, as shown below

	def user(name):
	print(f"Hi {name}")
	print("It is a good day to learn Python")
	user("Billy")

view raw function.py hosted with ❤ by GitHub

 

That’s all for now, I’ll be posting a continuation on this later on.

Comments

[HOBBOLT]

Billy!
As i learn python, would you be willing to help me develop an app? I am so new to coding.