# Learn by Doing – Learn Python By Examples Part 1 #### KtmBytes Python By Example 1:Printing Hello World in PythonCode:

``print("Hello World!")``

Output: `Hello World!`

#### KtmBytes Python By Example 1:Adding Two NumbersCode:

``````num1=1
num2=5
num = num1+num2
print("Adding ",num1," and", num2 , " gives", num)``````
Output: Adding 1 and 5 gives 6
Code:
``````num1=input("input number 1:")
num2=input("input number 2:")
sum=float(num1)+float(num2)
print("the sum is :", sum)``````

#### KtmBytes Python By Example 1:Area of a triangleCode:

``````a=3
b=5
c=6
s=(a+b+c)/2
area=(s*(s-a)*(s-b)*(s-c))**0.5
print("The Area of the triangle is :", area)``````
`The Area of the triangle is : 7.483314773547883`

#### KtmBytes Python By Example 1:Printing Hello World in PythonCode:

``````#swapping two variables
x=1.5
y=7

temp=x
x=y
y=temp
print("x = ",x,"y = ",y)``````

#### KtmBytes Python By Example 1:Finding roots of Quadratic Equation in PythonCode:

``````#finding Roots of Quadratic Equations
import cmath
a=1
b=6
c=8

d=(b**2)-(4*a*c)
root1=(-b-cmath.sqrt(d))/(2+a)
root2=(-b+cmath.sqrt(d))/(2+a)
print("The roots are :",root1, root2)``````

#### KtmBytes Python By Example :Converting Celsius to Fahrenheit in PythonCode:

``````#converting celsius to fahrenheit

celsius=36.5
fah=(celsius*1.8)-32
print('%0.1f deg Celsius = %0.1f deg Fahrenheit'%(celsius,fah))``````

#### KtmBytes Python By Example :Odd or even using pythonCode:

``````#check if the number is odd or even
num=input("enter a number :")
num=int(num)
if num>0:
if num%2==0:
print("The number is Even")
else:
print("The number is odd")
else:
print("The number is negative number")``````

#### KtmBytes Python By Example :Finding out a leap year in PythonCode:

``````#Leap Year
year=int(input("enter a year :"))

if year%4==0:
if year%100==0:
if year%400==0:
print("{0} is a leap year".format(year))
else:
print("{0} is not a leap year".format(year))
else:
print("{0} is a leap year".format(year))
else:
print("{0} is not leap year".format(year))``````

#### KtmBytes Python By Example :Prime number using PythonCode:

``````#prime number
num=int(input("enter a num :"))

if num>1:
for i in range(2,num):
if (num%i)==0:
print("The number is not a prime no")
break
else:
print("{0} is prime number.".format(num))
else:
print("The number is not a prime no")``````

#### KtmBytes Python By Example :Printing all the prime no in rangeCode:

``````#print all prime numbers in an interval

low=int(input("enter a lower range :"))
upp=int(input("enter a upper range :"))
print("prime no. between",low, "and",upp,"are :")

for num in range(low,upp + 1):
if num>1:
for i in range(2, num):
if (num%i)==0:
break
else:
print(num)``````

#### KtmBytes Python By Example Part : Factorial of a number Code:

``````#to find the factorial of a number
num= int(input("enter a number :"))
f=1
if num<0:
print("Sorry factorial does not exist for negative numbers")
elif num==0:
print("Factorial of 0 is 1")
else:
for i in range (1,num+1):
f = f * i
print("Factoriall of ",num, " is : ",f)``````