Iterative Statements

These are statements within our program which are repeatedly executed.
To repeatedly execute statements Python provide us three different looping structure.

while loop
for loop

While loop

It is used to repeatedly execute statements as long as a condition is true.

Execution of while loop

Python while loop is used to repeatedly execute some statements until the condition is true.
The while statement works with a condition rather than a sequence. The condition states that the while statement should perform a task until the condition is no longer true.
First condition is checked If condition is true, then statement within while loop are executed and again condition is checked The above process is repeated while the condition is true.
Program control is transferred to next statements only when condition becomes false.

Syntax:

while condition :
  statement
  ---------
  ---------
next statements

#Write a program to print all numbers from 1 to 10.

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

#Write a program to print all numbers from 1 to 10.

i=1
While i<=10:
  print(i,end=' ')
  i=i+1

1 2 3 4 5 6 7 8 9 10

#Write a program to print all numbers from 10 to 1.

i=10
while i>=1:
  print (i,end=' ')
  i=i-1

10 9 8 7 6 5 4 3 2 1

#Write a program to print all odd nos in range 1 to 100.

i=1
while i<=100:
  print(i,end=' ')
  i=i+2

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99

#Write a program o print all even nos in range 1 to 100.

i=2
while i<=100:
  print(i,end=' ')
  i=i+2

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100

#Write a program to print all even nos in range 1 to 100.

i=1
while i<=100:
  if i % 2==0 :
    print(i,end=' ')
  i=i+2

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100

#Write a program to read a number and to print all nos from 1 to given number.

a=int(input("Enter a Number "))
i=1
while i<=a:
  print(i,end=' ')
  i=i+1

Enter a Number: 12
1 2 3 4 5 6 7 8 9 10 11 12

#Write a program to read a number and print all odd nos from 1 to given number.

a=int(input("Enter a Number "))
i=1
while i<=a:
  print(i,end=' ')
  i=i+2

Enter a Number: 25
1 3 5 7 9 11 13 15 17 19 21 23 25

#Write a program to read a number and print all even nos from 1 to given number.

a=int(input("Enter a Number "))
i=2
while i<=a:
  print(i,end=' ')
  i=i+2

Enter a Number: 24
2 4 6 8 10 12 14 16 18 20 22 24

#Write a program to read 2 numbers A and B and print all numbers from A to B . ( assume A < B ).

a,b=input("Enter 2 Numbers ").split()
a,b=int(a),int(b)
while a<=b:
  print(a,end=' ')
  a=a+1

Enter 2 Number: 12 24
12 13 14 15 16 17 18 19 20 21 22 23 24

#Write a program to read 2 numbers A and B and print all numbers from A to B . ( assume A > B ).

a,b=input("Enter 2 Numbers ").split()
a,b=int(a),int(b)
while a>=b :
  print(a,end=' ')
  a=a-1

Enter 2 Number: 50 35
50 49 48 47 46 45 44 43 42 41 30 39 38 37 36 35

#Write a program to read 2 numbers A and B and print all numbers from A to B.

a,b=input("Enter 2 Numbers ").split()
a,b=int(a),int(b)
if a<b :
  while a<=b:
    print(a,end=' ')
    a=a+1
else:
  while a>=b :
    print(a,end=' ')
    a=a-1

Enter 2 Number: 50 35 
50 49 48 47 46 45 44 43 42 41 30 39 38 37 36 35 
Enter 2 Number: 12 24
12 13 14 15 16 17 18 19 20 21 22 23 24

#Write a program to print Amravati 10 times.

i=1
while i<=10:
  print("Amravati")
  i=i+1

Amravati 
Amravati
Amravati 
Amravati 
Amravati 
Amravati 
Amravati
Amravati 
Amravati

#Write a program to read 10 numbers and find their sum.

i=1
s=0
while i<=10 :
  a=int(input("Enter a Number"))
  s=s+a
  i=i+1
print("Sum is ",s)

Enter a Number 5 
Enter a Number 15
Enter a Number 5
Enter a Number 5
Enter a Number 10
Enter a Number 5
Enter a Number 5 
Enter a Number 25
Enter a Number 5
Enter a Number 5
Sum is 85

#Write a program to read 10 numbers and find sum of even numbers entered.

i=1
s=0
while i<=10:
  a=int(input("Enter a Number"))
  if a%2==0:
    s=s+a
  i=i+1
print("Sum of even numbers is ",s)

Enter a Number 12
Enter a Number 15 
Enter a Number 2
Enter a Number 5
Enter a Number 10
Enter a Number 6
Enter a Number 5
Enter a Number 25
Enter a Number 8
Enter a Number 5
Sum of even numbers is 38

#Write a program to read 10 numbers and find sum of even and odd numbers.

i=1
s1,s2=0,0
while i<=10 :
  a=int(input("Enter a Number"))
  if a%2==0 :
    s1=s1+a
  else:
    s2=s2+a
  i=i+1
print("Sum of even nos is ",s1)
print("Sum of odd nos is ",s2)

Enter a Number 5 
Enter a Number 15
Enter a Number 5 
Enter a Number 5 
Enter a Number 10 
Enter a Number 5 
Enter a Number 5 
Enter a Number 20
Enter a Number 5
Enter a Number 5 
Sum of even nos is 30
Sum of odd nos is 55

while….else loop

It is used to repeatedly execute statements as long as a given condition is true.
else block will execute when condition becomes false.
if loop is terminated without condition becoming false then else will not be executed.
else block is optional.

Syntax:

while condition :
    statements
    ----------
else:
    statements
    ----------

#Write a program to read a number and check if it is a prime number or not.

n=int(input("Enter a number"))
i=2
while i<n:
  if n%i==0:
    print("Number is not prime")
    break
  i=i+1
else:
  print("Number is prime")

Enter a Number: 9 
Number is not prime
Enter a Number:
Number is prime

CCITcoder

Introduction to Python

Conditional statements

Iterative statements

Functions

OOPs

Collection

Module and Exception

DateBase

Inherintance

GUI