DEV Community: Keerti Sadana S

PYTHON - PATTERNS 3

Keerti Sadana S — Thu, 03 Sep 2026 11:44:50 +0000

Diamond Pattern:

for row in range(1,6):
    for col in range(1, 6-row):
        print(end=' ')
    for col in range(1,row+1):
        print('*',end=' ')
    print()

for row in range(1,6):
    for col in range(1, row+1):
        print(end=' ')
    for col in range(1,6-row):
        print('*',end=' ')
    print()

Output:

    * 
   * * 
  * * * 
 * * * * 
* * * * * 
 * * * * 
  * * * 
   * * 
    *

Floyd Triangle:

no = 1
for row in range(1,6):
    for col in range(1,row+1):
        print(no,end=' ')
        no+=1
    print()

Output:

1 
2 3 
4 5 6 
7 8 9 10 
11 12 13 14 15

Pattern:

for row in range(1,6):
    for col in range(row):
        print(col % 2, end=" ")
    print()

Output:

PYTHON - PATTERNS 2

Keerti Sadana S — Wed, 02 Sep 2026 14:29:49 +0000

Pattern 1:

for row in range (1,6):
    for col in range (1,row+1):
        print('*',end = ' ')
    print()

Output:

Pattern 2:

for row in range(1,6):
    for col in range(1,row+1):
        print(col,end=' ')
    print()

Output:
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5

Pattern 3:

for row in range(1,6):
    for col in range(1,row+1):
        print(row,end=' ')
    print()

Output:
1
2 2
3 3 3
4 4 4 4
5 5 5 5 5

Pattern 4:

for row in range(1,6):
    for col in range(1,row+1):
        print(col*row,end=' ')
    print()

Output:
1
2 4
3 6 9
4 8 12 16
5 10 15 20 25

PYTHON - PATTERNS 1

Keerti Sadana S — Wed, 02 Sep 2026 14:20:19 +0000

Pattern 1:

num = 0
for row in range(5,0,-1):
    for col in range(1,row+1):
        print(col+num,end = '   ')
    num+=row
    print()

Output:
1 2 3 4 5

6 7 8 9

10 11 12

13 14

15

Pattern 2:

value = 64
for row in range(5,0,-1):
    no = 1
    for col in range(1,row+1):
        print(chr(value+no),end = ' ')
        no+=1
    num+=row
    print()

Output:
A B C D E
A B C D
A B C
A B
A

Pattern 3:

value = 64
for row in range(1,6):
    no = 1
    for col in range(1,row+1):
        print(chr(value+no),end = ' ')
        no+=1
    num+=row
    print()

Output:
A
A B
A B C
A B C D
A B C D E

PYTHON - LOOPS 9

Keerti Sadana S — Sun, 30 Aug 2026 14:59:01 +0000

Perfect Numbers:

no = 6
total = 1
div = 2
while div<no:
    if no%div == 0:
        total += div
    div += 1
else:
    if total == no:
        print ('Perfect Number')
    else:    
        print ('Not a Perfect Number')

Output:
Perfect Number

Prime and Composite Numbers between 1 and 31:

no = 2
print('Composite Numbers:')
while no < 31:
    div = 2
    while div<=no//2:
        if no%div == 0:
            print(no,end = ' ')
            break
        div+=1
    no+=1

print('\n')

no = 2
print('Prime Numbers:')
while no < 31:
    div = 2
    while div<=no//2:
        if no%div == 0:
            break
        div+=1
    else:
        print(no,end=' ')
    no+=1

Output:
Composite Numbers:
4 6 8 9 10 12 14 15 16 18 20 21 22 24 25 26 27 28 30

Prime Numbers:
2 3 5 7 11 13 17 19 23 29

Sum of two consecutive prime numbers:

def is_prime(no):
    div = 2
    while div <= no//2:      
        if no % div == 0:
            return False
        div+=1
    else:
        return True
no = 42
prime1 = 2
while (prime1<no):
    prime2 = prime1 + 1
    while not is_prime(prime2):
        prime2 += 1
    if prime1+prime2 == no:
        print (f'{prime1} + {prime2} = {no}')
        break
    prime1 = prime2

Output:
19 + 23 = 42

Sum of three consecutive prime numbers:

def is_prime(no):
    div = 2
    while div <= no//2:      
        if no % div == 0:
            return False
        div+=1
    else:
        return True
no = 31
prime1 = 2
while (prime1<no):
    prime2 = prime1 + 1
    while not is_prime(prime2):
        prime2 += 1
    prime3 = prime2 + 1
    while not is_prime(prime3):
        prime3 += 1
    if prime1+prime2+prime3 == no:
        print (f'{prime1} + {prime2} + {prime3} = {no}')
        break
    prime1 = prime2
    prime2 = prime3

Output:
7 + 11 + 13 = 31

Divisible by 2:

no = 234
if (no%10)%2 == 0:
    print ('Divisible by 2')

Output:
Divisible by 2

Divisible by 3:

no = 654321
total = 0
while no>0:
    total += no%10
    no//=10
if total%3 == 0:
    print('Divisible by 3')

Output:
Divisible by 3

Divisible by 4:

no = 124
if (no%100)%4 == 0:
    print ('Divisible by 4')

Output:
Divisible by 4

Divisible by 5:

no = 35
if no%10 in (0,5):
    print ('Divisible by 5')

Output:
Divisible by 5

Divisible by 6:

no = 138
if (no%10)%2 == 0 and (no%10 + no//10)%3 == 0:
    print ('Divisible by 6')

Output:
Divisible by 6

Divisible by 8:

no = 2992
if (no%1000)%4 == 0:
    print ('Divisible by 8')

Output:
Divisible by 8

Divisible by 9:

no = 9567
total = 0
while no>0:
    total += no%10
    no//=10
if total%3 == 0 and total%9 == 0:
    print('Divisible by 9')

Output:
Divisible by 9

Divisible by 10:

no = 30
if no%10 == 0:
    print ('Divisible by 10')

Output:
Divisible by 10

Divisible by 11:

no = 256795
odd_position = 0
even_position = 0
position = 1
while no > 0:
    if position % 2 != 0:
        odd_position += no%10
    else:
        even_position += no%10  
    no //= 10  
    position += 1  

if odd_position - even_position == 0:
    print('Divisible by 11')

Output:
Divisible by 11

PYTHON - LOOPS 8

Keerti Sadana S — Fri, 21 Aug 2026 19:00:55 +0000

1) Double Number

no = int(input('Enter a Number: '))
if no > 9 and no < 100:
    print ( f'{no} is double Number')

OUTPUT:
Enter a Number: 54
54 is double Number
2) Neon Number
A neon number is a number where the sum of the digits of its square is equal to the number itself.
For example, 9 is a neon number because 9² = 81 and the sum of its digits is 8 + 1 = 9.

def sum (n):
    total = 0
    while n > 0:
        total = total + n%10
        n//=10
    return total
no = int(input('Enter a Number: '))
square = no**2
result = sum(square)
if no == result :
    print ('Neon Number')
else:
    print ('Not a Neon Number')

OUTPUT:
Enter a Number: 9
Neon Number
3)Strong Number
A strong number is a positive number where the sum of the factorials of its digits equals the number itself. For example, 145 is a strong number because 1! + 4! + 5! = 1 + 24 + 120 = 145.

def fact(n):
    if n == 1:
        return 1
    else:
        return n*fact(n-1)
def sum (n):
    total = 0
    while n >0:
        total = total + fact(n%10)
        n//=10
    return total
no = int(input('Enter a Number: '))
result = sum(no)
if no == result :
    print ('Strong Number')
else:
    print('Not a Strong Number')

OUTPUT:
Enter a Number: 145
Strong Number
4) Automorphic Number
An automorphic number is an integer whose square ends with the exact same digits as the number itself.
For example, 5² = 25 ends in 5, and 76² = 5776 ends in 76.

def count_of_digits (n):
    count = 1
    while n > 0:
        count *= 10
        n//=10
    return count
no = int(input('Enter a Number: '))
square = no ** 2
count = count_of_digits(no)
if (no == square%count):
    print('Automorphic number')
else:
    print('Not an Automorphic number')

OUTPUT:
Enter a Number: 25
Automorphic number
5) Duck Number
A duck number is a positive number that contains at least one zero digit, provided the zero does not appear at the very beginning of the number.

no = input('Enter a Number: ')
if no[0] == '0' or '0' not in no:
    print('Not a Duck number')
else:
    if '0' in no :
        print('Duck Number')

OUTPUT:
Enter a Number: 125063
Duck Number
6) Spy Number
A spy number is a positive integer where the sum of its digits equals the product of its digits. For example, 1124 is a spy number because (1 + 1 + 2 + 4 = 8) and (1 \times 1 \times 2 \times 4 = 8).

def sum (n):
    total = 0
    multiply = 1
    while n >0:
        total = total + n%10
        multiply *= n%10
        n//=10
    return total == multiply
no = int(input('Enter a Number: '))
result = sum(no)
if result:
    print('Spy Number')
else:
    print('Not a Spy Number')

OUTPUT:
Enter a Number: 1124
Spy Number

PYTHON - LOOPS7

Keerti Sadana S — Fri, 21 Aug 2026 18:41:59 +0000

1) Count of Digits, Sum of Digits, Reverse Digit and Palindrome

no = int(input("Enter any Number: "))
copy = no
sum = 0
count = 0
reverse = 0
while no > 0:
    rem = no%10
    reverse = (reverse*10) + rem 
    sum = sum + rem 
    no = no//10
    count += 1

print(f'Count of Digits is {count}')
print(f'Sum of Digits is {sum}')
print(f'Reverse Digit is {reverse}')

if (copy == reverse):
    print('Palindrome')
else:
    print('Not a Palindrome')

OUTPUT:
Enter any Number: 1221
Count of Digits is 4
Sum of Digits is 6
Reverse Digit is 1221
Palindrome
2) user input number: 123456 -> 2 + 4 + 6

no = 123456
total = 0
while no>0:
    print((no%100)%10)
    total = total + (no%100)%10
    no//=100
print(total)

OUTPUT:
6
4
2
12
3) user input number: 123456 -> 56 34 12 and its sum

no = 123456
total = 0
while no>0:
    total = total+(no%100)
    print (no%100)
    no//=100
print(total)

python
OUTPUT:
56
34
12
102
4) user input number: 123456 -> 456 123

no = 123456
total = 0
while no>0:
    total = total+(no%1000)
    print (no%1000)
    no//=1000
print(total)

OUTPUT:
456
123
579
5) user input number: 123456 -> 56 45 34 23 12

no = 123456
total = 0
while no>1:
    total = total+(no%100)
    print (no%100)
    no//=10
print(total)

OUTPUT:
56
45
34
23
12
170
6) user input number: 123456 -> 1+3+5 [tbd]

PYTHON - LOOPS 6

Keerti Sadana S — Wed, 19 Aug 2026 16:31:00 +0000

**16) Secret VIP Numbers

A security system assigns special numbers to the first few VIP lockers. A number is considered a VIP number if it can be divided exactly by only 1 and itself. The security officer wants the numbers of the first 5 VIP lockers. Write a Python program to display those 5 numbers.

Expected Result: 2, 3, 5, 7, 11
**

def vip_number(n):
    div = 2
    while div <= n//2:
        if n%div == 0:
            return 'not VIP'
        div += 1
    else:
        return 'VIP'
count = 0
n = 2
while count < 5:
    result = vip_number(n)
    if result == 'VIP':
        print(n)
        count += 1
        n += 1
    else:
        n+= 1

OUTPUT:
2
3
5
7
11
*17) The Special Numbers
A teacher is preparing a Number Exhibition for students. She writes the numbers 1 to 20 on 20 cards. She wants to select only the special cards. A card is special if its number can be divided exactly by only two numbers: 1 and the number itself.

The teacher asks the students:
“Check all the cards from 1 to 20 and display the numbers that are special.”
*

def special_number(n):
    div = 2
    while div <= n//2:
        if n%div == 0:
            return 'not special'
        div += 1
    else:
        return 'special'
n = 2
while n <= 20:
    result = special_number(n)
    if result == 'special':
        print(n)
        n += 1
    else:
        n+= 1

OUTPUT:
2
3
5
7
11
13
17
19

18) You have Rs. 100/-. One chocolate costs Rs. 5. Every time you buy a chocolate, you get one wrapper. You can exchange 3 wrappers for 1 additional chocolate. What is the maximum number of chocolates you can have with Rs. 100?

chocolate = 20
wrapper = 20
while wrapper >= 3:
    wrapper -= 3
    wrapper += 1
    chocolate += 1
print (chocolate)

OUTPUT:
29
*19) There is one person called Viyan. He is a Software Engineer. He employs a maid for cooking. One day, the maid prepared n number of chapathis and kept them in a hot box. Viyan ate those chapathis, and the count is as follows:
* For Morning breakfast, he consumed 1/3 of the chapathis in the hot box.
* For Lunch, He had 1/3 of what was there in the hot box.
* For Dinner, again he took and ate 1/3 of the chapathis present in the box.

The next morning, when the maid checked the number of chapathis remaining, it was 8. What was the number of chapathis she made in total?
*

balance = 8
count = 1
while count<=3:
    eaten = balance // 2
    balance += eaten
    count += 1
print('Total number of chappathis : ',balance)

OUTPUT:
Total number of chappathis: 27

PYTHON - LOOPS 5

Keerti Sadana S — Wed, 19 Aug 2026 15:48:05 +0000

**14) Two trains stop at regular intervals:
Train 1 stops at every 3rd station.
Train 2 stops at every 5th station.
Find:
The first common station where both trains stop.
The last common station where both trains stop.
All common stations where both trains stop.

Note: The total number of stations is unknown.**

station = 3
last_station = 0
first_station = True
while station <= 80:
    if station % 3 == 0 and station % 5 == 0:
        if first_station == True:
            print("First Common Station is", station)
            first_station = False
        last_station = station
        print(station)
    station+=1
print("Last Common Station is", last_station)

OUTPUT
First Common Station is 15
15
30
45
60
75
Last Common Station is 75

**15) A school is preparing a large square floor for its annual function. The floor has N tiles arranged in a single row. The teacher wants to divide these tiles into equal-sized groups without leaving any tile unused. For example, if there are 12 tiles, the teacher can make:

1 group of 12 tiles
2 groups of 6 tiles
3 groups of 4 tiles
4 groups of 3 tiles
6 groups of 2 tiles
12 groups of 1 tile

Write a Python program that takes the number of tiles N and finds all possible group sizes that can divide the tiles equally.**

no = 12
div = 1
while div <= no:
    if no % div == 0:
        print(div)
    div+=1

OUTPUT
1
2
3
4
6
12

PYTHON TASKS - LOOPS4

Keerti Sadana S — Wed, 12 Aug 2026 14:07:23 +0000

12)Tenali Raman and the Palace Guards

Tenali Raman wishes to meet the King. Before reaching the royal court, he has to pass through many palace gates. A guard is posted at each gate. Every guard demands a share of whatever reward Tenali Raman receives from the King. Tenali Raman agrees and promises: "I will give you half of whatever reward I receive from the King."

All the guards allow him to enter. After meeting the King, Tenali Raman receives a reward of 1024 lashes. Keeping his promise, Tenali Raman shares his reward with the guards. At each gate, he gives half of the lashes he still has to receive to the guard at that gate and proceeds to the next gate.

Write a program to determine: சவுக்கடி

How many lashes each guard receives.
How many Guards are there if Tenali Raman gets only one lash.

lashes = 1024
guard = 0
while lashes > 1:
    lashes//=2
    guard += 1
    print('Guard',guard,'=',lashes)

print('Total number of guards:',guard)

Output:
Guard 1 = 512
Guard 2 = 256
Guard 3 = 128
Guard 4 = 64
Guard 5 = 32
Guard 6 = 16
Guard 7 = 8
Guard 8 = 4
Guard 9 = 2
Guard 10 = 1
Total number of guards: 10

13)Thief, Police Running

police = 0
step = 0
thief = 40
while police<thief:
    police += 5
    thief += 2
    step += 1
print(police)
print('Total number of steps to catch the thief: ',step)

Output:
70
Total number of steps to catch the thief: 14

PYTHON TASK - LOOPS3

Keerti Sadana S — Wed, 12 Aug 2026 13:56:28 +0000

8) A king announces a unique reward for Hard Workers. On each day, the reward is multiplied by the day's number. The reward starts at 1 gold coin. Given the number of days n, write a program to calculate the final reward.
2 = 2 * 1
3 = 3 * 2 * 1
4 = 4 * 3 * 2 * 1

n = int(input('Enter total number of days: '))
days = 1
coin = 1
while days<=n:
    coin *= days
    days += 1
print ('The final reward = ',coin)

Output:
Enter total number of days: 5
The final reward = 120

*9) Suppose a password consists of the letters:
A, B. Each letter must be used exactly once. How many different passwords are possible?
ABCD, ABDC, ACBD, ACDB, ADBC, ADCB, BACD, BADC, BCAD, BCDA, BDAC, BDCA, CABD, CADB, CBAD, CBDA, CDAB, CDBA, DABC, DACB, DBAC, DBCA, DCAB, DCBA
*

n = 4
possible = 1
while n>=1:
    possible *= n
    n-=1
print(possible)

Output:
24

**10)Frog in a Well
A frog accidentally falls into a 60-foot-deep well.
Every day:

During the day, the frog climbs 2 feet.
During the night, it slips down 0.5 feet.

This pattern continues every day until the frog reaches the top of the well and escapes.

Write a program to determine:

How many days it takes for the frog to get out of the well.
On which day the frog escapes. ** Note: Once the frog reaches or crosses the top of the well during the daytime, it escapes immediately and does not slip back that night.

total_foot = 60
up = 2
down = 0.5
days = 0
while total_foot>0:
    total_foot -= up
    total_foot += down
    days +=1
print('Total number of days taken = ',days)
print('The day frog reached = ',days)

Output:
Total number of days taken = 40
The day frog reached = 40

**11)The Saint's Flower Basket

A saint goes for a morning walk every day. During his walk, he plucks flowers and keeps them in a basket. On his way back home, he visits 7 temples. At each temple, he offers half of the flowers currently in his basket.

After visiting all 7 temples, he reaches home with exactly one flower remaining in his basket.

final(after)

1

Write a program to determine how many flowers the saint had in his basket before he visited the first temple.
**
Hint: Think carefully about whether it is easier to solve the problem from the beginning or by working backwards from the final flower.

flower_basket = 1
temple = 7
while temple > 0:
    flower_basket *= 2
    temple -= 1
print ('Flowers the saint had in his basket before he visited the first temple:',flower_basket)

Output:
Flowers the saint had in his basket before he visited the first temple: 128

Python Tasks - LOOPS1

Keerti Sadana S — Wed, 05 Aug 2026 14:28:34 +0000

Task 1
A teacher asks five students to stand in a line. Each student wears a badge with the number 1. Display the badge numbers from left to right.

For loop:

While loop:

Output:

Task 2
Five students enter the classroom one after another. The first student gets roll number 1, the second gets 2, and so on. Display the assigned roll numbers.
For loop:

While loop:

Output:

Task 3
A coach asks students to stand only at even-numbered positions in a queue. Display the first five positions.
For loop:

While loop:

Output:

Task 4
A newly constructed building has a special lift that does not stop on every floor. For safety reasons, it stops only at every third floor. A person enters the lift at the ground floor and presses the "Up" button.

Display the first five floors where the lift will stop.
For loop:

While loop:

Output:

Task 5
A rocket launches with a countdown using only even numbers. Display the countdown.
For loop:

While loop:

Output:

PYTHON - Functions,Arguments,Module,Error Types

Keerti Sadana S — Mon, 03 Aug 2026 18:01:14 +0000

What is a function?
-> It is a block of code used to perform a specific task.
-> It can be reused.

How to define a function?
-> It is defined using the keyword def.
Syntax:

Example:-
code:
def fun():
print("Welcome to GFG")

Function calling:
def fun():
print("Welcome to GFG")
fun() #function calling
Output:
Welcome to GFG.

What are Arguments?
-> Arguments are variables that are passed to a function during a function call.
Syntax:

Types of Arguments (tbd):
-> Positional Arguments
-> Keyword Arguments
-> Default Arguments
-> Variable Length Arguments

How to check the type of variable or function?
-> The type of a variable or function can be checked using the type() function.
Code :
def add(no1, no2):
return no1 + no2
developer = 'nimal anand'
print(type(add))
print(type(developer))

Duck-Typed Language:
-> Duck typing means the computer cares about what something can do, not what it is.
-> Datatypes are not explicitly mentioned
-> Python is a duck-typed language.

What is modularity?
-> Modularity means breaking a big program into smaller, easier-to-manage parts (modules).
-> Easy maintenance.

What is a module?
-> A module is a file that contains code for a specific task, so you can reuse it whenever you need it.
code:

Output:
250
Members of module:
-> function - add
-> variable - name

Types of Errors:
-> TypeError
-> NameError
-> SyntaxError
-> ModuleNotFoundError

TypeError:
-> It is raised when an operation or function is applied to an object of an inappropriate type.
Examples:

Adding a string and an integer
Using len() on an integer
Calling a function with the wrong number of arguments

NameError:
-> A NameError is raised when a variable or function name is not defined.
Example:

Variable not defined
Misspelt variable name