Iterative Statements

Iterative statements: for loop, range function, while loop, flowcharts, break and continue statements, nested loops, suggested programs: generating pattern, summation of series, finding the factorial of a positive number etc 

Looping (Iterative) statements :

1.These statements are used to repeat a code of block for given condition.

2.The iteration statements are called loops or looping statements.

3.Every time when loop body is executed called an iteration.

4.Python support two looping statements for and while.

5.Both are entry control loop

6.Python does not offer exit control loop

7.Looping statements have optional else clause in python. Else block is executed if loop body terminated normally.

8.break statement can be used to stop a for loop. In such case, the else part is ignored.

for loop :

1.It is  used to iterate over a sequence  such as list, tuple or string one by one.

2. Iterating over a sequence is called traversal.

else block will be executed only when Loop terminated normally. If loop terminated with break statement  then else block will not executed

In Python, break and continue statements can alter the flow of a normal loop. 

break : statement is used to exit from Loop block

L=[1,2,3,4,5,6,7,8,9,10]

for i in L:

    print(i)

    if(i==5):

          break

Output

 1 2 3 4 5 

range()  Function

The range() function returns a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and ends at a specified number.

Syntax

range(start, stop, step)

start and step is optional but stop is required. step value is by default 1 and start value is by default 0

e.g

for i in range(1,6):

  print(i)

Output 1 2 3 4 5

Statement  Output

range(3, 20, 2)   3 5 7 9 11 13 15 17 19

range(5,10)  5,6,7,8,9

range(9,3,-1)  9 8 7 6 5 4

range(10,1,-2)  10 8 6 4 2

#Write a program to find the sum of all digits of a given number.

n=int(input("enter a numbr"))

s=str(n)

sum=0 

for i in s:

    sum=sum+int(i)

print(sum)

Write a program to find out the reverse of a given number.

n=int(input("enter a number"))

s=str(n)

str = "" 

for i in s:

    str = i + str

n=int(str)

print(n)

WAP to print triangle :

1 

1 2 

1 2 3 

1 2 3 4 

1 2 3 4 5 

for i in range(6):

    for j in range(i):

        print(j+1,end=" ")

    print()

WAP to print triangle :

1

2 2

3 3 3

4 4 4 4

5 5 5 5 5 

for i in range(6):

    for j in range(i):

        print(i,end=" ")

    print()

WAP to print triangle

1

2    3

4    5 6

7    8 9 10

11  12  13  14   15 

k=1

for i in range(6):

    for j in range(i):

        print(k,end=" ")

        k=k+1

    print()

WAP to print triangle

* 

* * 

* * * 

* * * * 

* * * * * 

k=‘*’

for i in range(6):

    for j in range(i):

        print(k,end=" ")

     print()

#WAP to enter a string and check it is palindrome or not

s=input("enter a string")

str = "" 

for i in s:

    str = i + str

if(s==str):

    print("Palindrome")

else:

    print("Not Palindrome")

#WAP to calculate the length of a string

s='COMPUTER SCIENCE '

c = 0

for i in s:

 c += 1

print(c)

Write Python script to print the following pattern :

1

1  3

1  3  5

1  3  5   7

ans.

for a in range(3, 10, 2) :

for b in range(1, a, 2) :

print (b, end = ‘ ‘)

      print()

# WAP to print 1 to 10 natural numbers

1 2 3 4 5 6 7 8 9 10

for i in range(1,11,1):

  print(i)

# WAP to print table of given number

n=int(input("Enter a number"))

for i in range(1,11,1):

  print(i*n)

Write a program to print the following using a single loop (no nested loops)

1

1 1

1 1 1

1 1 1 1

1 1 1 1 1

n = 1

for a in range(5) :

print(n)

n = n*10+1

# program to print