Introduction: Python Basics

Python is easy to use, powerful, and versatile, making it a great choice for beginners and experts alike. Python’s readability makes it a great first programming language — it allows you to think like a programmer and not waste time with confusing syntax. For instance, look at the following code to print “hello world” in Java and Python.

public classMain{
    public static void main{
        system.out.printline("hello world");
    }

}

print("hello world")

why python

Variables

Variables in python are very flexible, unlike C++:

  • Interpreted language.
  • No need to declare the variable type.
  • The same variable can be assigned to different types.
x = 5
y = 'Hello SBME'
z = 5
z = "Hello SBME"

Lists

# List construction
subjects = ['Technical Writing','Computer Vision']

# Append an element
subjects.append('Biochemistry')

# Append another list
subjects.extend(['Bioelectronics','Stochastic'])

print( subjects ) # ??
print( subjects[0] ) # ??
print( subjects[1] ) # ??

Arithmetic Operations


x = 19
y = 18 

z = x / y
z = x * y
z = x + y
z = x - y

Logical Opertations

x = 17 % 2 == 1

y = 9 / 3 < 1 

b = x or y ## True

b = x and y ## False

  • and => && in C++

  • or => || in C++

If, elif, else


x = 23 
y = 22 

if x < y:
  z = 13 # Local scope

elif x % 2 == 1 and x > y :
  h = 17 # Local scope

else:
  v = 80 # Local scope

print( z ) # Error: z is out of scope
print( h ) # Error: h is out of scope

Loops


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

i = 0
while i < 10 :
  print( i )
  i += 1

Functions

def mean( list ):
  sum = 0
  for element in list:
    sum += element
  return sum / len( sum )

m = mean([1,12,42,1,23,12])
print( m )