2. Looping (or) Iterative (or) Repetitive Statements

The purpose of looping statements is to perform a specific operation repeatedly for a finite number of times until the test condition becomes false.

In Python programming, there are two types of looping statements:

for loop (or for...else loop)
while loop (or while... else loop)

When working with while loops in Python, ensure the following three components are included.

Initialization part

Conditional part

Updation part (increment or decrement)

For Loop

The purpose of a for loop is to retrieve or extract data from any iterable object.

for varname in iterable_object: # Block of statements # Other statements in the program

for varname in iterable_object: # Block of statements else: # Else block of statements # Other statements in the program

# Write a program to generate numbers from 1 to 10 num = int(input("enter the number = ")) for var in range(10): print(var)

# Write a program to generate 1 to 20 even number num = int(input("Enter the given number = ")) for var in range(0,num,2): print(var, end = " ")

# Write a program to find given number is prime or not num = int(input("enter the given number = ")) for var in range(2, num): if num % var == 0: print("Not Prime number") else: print("Prime Number")

# Write a program to find the factorial of a given number number = int(input("enter the given number = ")) fact = 1 for i in range(1,number+1): fact = fact*i print(fact)

The keywords for, in, and else are used.

varname is a programmer-defined variable.

An iterable_object is any object containing multiple values, such as a sequence (string, tuple), list, set, or dictionary.

The execution process of a for loop involves selecting each element from the iterable_object, assigning it to varname, and executing the block of statements. This process repeats for a finite number of times (equal to the length of the iterable_object) until all elements are processed.

When all elements of the iterable_object are processed, the for loop condition becomes false. If an else block is present, its statements are executed, followed by other statements in the program.

The else block is optional.

Note 1: For iterating over iterable objects, it is recommended to use a for loop.

Note 2: For repeating non-iterable objects, it is recommended to use a while loop.

# string str = "Hello" for var in str: print(var)

Nested for loop:

A nested for loop is a for loop inside another for loop, where the inner loop runs completely for each iteration of the outer loop. With strings, nested for loops are used to

Compare characters (e.g., finding duplicates).

Generate patterns (e.g., printing substrings).

Process combinations (e.g., anagrams or string matching).

for var1 in iterable_object1: # Outer loop block for var2 in iterable_object2: # Inner loop block # Optional outer else else: # Optional outer else block # Other statements

# Write a program to generate 1 to 100 even numbers for i in range(2,101): for j in range(2,i): if i%j == 0: break else: print(i,end = " ")