Important CS Programs

message = input("Enter a welcome message: ")
print("Your message is:", message)

# Sample run (the values after each prompt are typed by the user):
# Enter a welcome message: Welcome to CSIP12!
# Your message is: Welcome to CSIP12!

a = int(input("Enter first number: "))
b = int(input("Enter second number: "))
print("Sum =", a + b)

# Sample run (the values after each prompt are typed by the user):
# Enter first number: 25
# Enter second number: 17
# Sum = 42

p = float(input("Principal: "))
r = float(input("Rate of interest: "))
t = float(input("Time in years: "))
si = p * r * t / 100
print("Simple Interest =", si)
print("Total amount =", p + si)

# Sample run (the values after each prompt are typed by the user):
# Principal: 5000
# Rate of interest: 6.5
# Time in years: 2
# Simple Interest = 650.0
# Total amount = 5650.0

length = float(input("Length: "))
breadth = float(input("Breadth: "))
print("Area =", length * breadth)
print("Perimeter =", 2 * (length + breadth))

# Sample run (the values after each prompt are typed by the user):
# Length: 12
# Breadth: 7.5
# Area = 90.0
# Perimeter = 39.0

a = 10
b = 20
temp = a          # way 1: using a third variable
a = b
b = temp
print("After swap 1: a =", a, "b =", b)

a, b = b, a       # way 2: tuple assignment
print("After swap 2: a =", a, "b =", b)

# Output:
# After swap 1: a = 20 b = 10
# After swap 2: a = 10 b = 20

a = 17
b = 5
print("a + b  =", a + b)
print("a - b  =", a - b)
print("a * b  =", a * b)
print("a / b  =", a / b)      # division
print("a // b =", a // b)     # floor division
print("a % b  =", a % b)      # remainder
print("a ** 2 =", a ** 2)     # power

# Output:
# a + b  = 22
# a - b  = 12
# a * b  = 85
# a / b  = 3.4
# a // b = 3
# a % b  = 2
# a ** 2 = 289

x = 10          # int
y = 2.5         # float
z = x + y       # implicit: the result becomes float
print(z, type(z))

s = "45"
n = int(s) + 5            # explicit: str -> int
print(n)
print(str(100) + "%")     # explicit: int -> str
print(float("3.75") * 2)  # explicit: str -> float

# Output:
# 12.5 <class 'float'>
# 50
# 100%
# 7.5

x = 10
x += 5           # augmented assignment
x *= 2
print("x =", x)

a = [1, 2]
b = a
c = [1, 2]
print(a is b)        # True: same object
print(a is c)        # False: different objects with equal values
print(a == c)        # True: equal values
print(3 in [1, 2, 3])
print("z" not in "python")

# Output:
# x = 30
# True
# False
# True
# True
# True

print(19 < 11 and 29 > 19 or not 75 > 30)
print(True or False and False)
print(not (5 > 3))
age = 17
print(age >= 13 and age <= 19)    # is a teenager?

# Output:
# False
# True
# False
# True

print(14 % 3 ** 2 * 4)            # 3**2=9, 14%9=5, 5*4=20
print(16 * 5 / 4 * 2 / 5 - 8)
print(3 - 2 ** 2 ** 3 + 99 / 11)  # 2**3=8 first, then 2**8=256
print(10 - 3 ** 2 ** 2 + 144 / 12)
print(25 + 100 ** 1 ** 3 / 5)

# Output:
# 20
# 0.0
# -244.0
# -59.0
# 45.0

# Syntax error (the program will not start):
#     print("Hello"          <- missing )

# Runtime error (stops while running):
#     print("15" + 3)        <- TypeError: cannot add str and int
print("15" + str(3))         # fixed: joins text -> 153
print(int("15") + 3)         # fixed: adds numbers -> 18

# Logical error (runs, but the answer is wrong):
a, b = 10, 20
average = a + b / 2          # wrong: only b is divided
print("Wrong average:", average)
average = (a + b) / 2        # right
print("Right average:", average)

# Output:
# 153
# 18
# Wrong average: 20.0
# Right average: 15.0

n = int(input("Enter a number: "))
if n % 2 == 0:
    print(n, "is even")
else:
    print(n, "is odd")

# Sample run (the values after each prompt are typed by the user):
# Enter a number: 37
# 37 is odd

a = int(input("Enter first number: "))
b = int(input("Enter second number: "))
if a > b:
    print("Larger:", a, " Smaller:", b)
elif b > a:
    print("Larger:", b, " Smaller:", a)
else:
    print("Both numbers are equal")

# Sample run (the values after each prompt are typed by the user):
# Enter first number: 48
# Enter second number: 73
# Larger: 73  Smaller: 48

n = float(input("Enter a number: "))
if n < 0:
    n = -n
print("Absolute value:", n)

# Sample run (the values after each prompt are typed by the user):
# Enter a number: -12.5
# Absolute value: 12.5

n = int(input("Enter a number: "))
d = int(input("Check divisibility by: "))
if n % d == 0:
    print(n, "is divisible by", d)
else:
    print(n, "is not divisible by", d, "- remainder", n % d)

# Sample run (the values after each prompt are typed by the user):
# Enter a number: 84
# Check divisibility by: 7
# 84 is divisible by 7

a = int(input("First number: "))
b = int(input("Second number: "))
c = int(input("Third number: "))

if a >= b and a >= c:
    largest = a
elif b >= a and b >= c:
    largest = b
else:
    largest = c

if a <= b and a <= c:
    smallest = a
elif b <= a and b <= c:
    smallest = b
else:
    smallest = c

print("Largest:", largest)
print("Smallest:", smallest)

# Sample run (the values after each prompt are typed by the user):
# First number: 45
# Second number: 92
# Third number: 17
# Largest: 92
# Smallest: 17

a = int(input("First number: "))
b = int(input("Second number: "))
c = int(input("Third number: "))

if a > b:
    a, b = b, a       # now a <= b
if b > c:
    b, c = c, b       # now c is the largest
if a > b:
    a, b = b, a       # fix the first two again
print("Ascending order:", a, b, c)

# Sample run (the values after each prompt are typed by the user):
# First number: 30
# Second number: 10
# Third number: 20
# Ascending order: 10 20 30

per = float(input("Enter percentage: "))
if per >= 90:
    grade = "A1"
elif per >= 80:
    grade = "A2"
elif per >= 70:
    grade = "B1"
elif per >= 60:
    grade = "B2"
elif per >= 33:
    grade = "C"
else:
    grade = "Fail"
print("Grade:", grade)

# Sample run (the values after each prompt are typed by the user):
# Enter percentage: 76.5
# Grade: B1

year = int(input("Enter a year: "))
if (year % 4 == 0 and year % 100 != 0) or year % 400 == 0:
    print(year, "is a leap year")
else:
    print(year, "is not a leap year")

# Sample run (the values after each prompt are typed by the user):
# Enter a year: 1900
# 1900 is not a leap year

a = float(input("First number: "))
op = input("Operator (+ - * /): ")
b = float(input("Second number: "))

if op == "+":
    print("Result:", a + b)
elif op == "-":
    print("Result:", a - b)
elif op == "*":
    print("Result:", a * b)
elif op == "/":
    if b == 0:
        print("Cannot divide by zero")
    else:
        print("Result:", a / b)
else:
    print("Invalid operator")

# Sample run (the values after each prompt are typed by the user):
# First number: 15
# Operator (+ - * /): /
# Second number: 4
# Result: 3.75

ch = input("Enter one character: ")
if ch.isupper():
    print(ch, "is an uppercase letter")
elif ch.islower():
    print(ch, "is a lowercase letter")
elif ch.isdigit():
    print(ch, "is a digit")
else:
    print(ch, "is a special character")

# Sample run (the values after each prompt are typed by the user):
# Enter one character: @
# @ is a special character

a = float(input("Side 1: "))
b = float(input("Side 2: "))
c = float(input("Side 3: "))
if a + b > c and b + c > a and a + c > b:
    if a == b == c:
        print("Equilateral triangle")
    elif a == b or b == c or a == c:
        print("Isosceles triangle")
    else:
        print("Scalene triangle")
else:
    print("These sides cannot make a triangle")

# Sample run (the values after each prompt are typed by the user):
# Side 1: 5
# Side 2: 5
# Side 3: 8
# Isosceles triangle

for k in range(7, 40, 6):
    print(k, end='-')
print()
for i in range(10, 0, -2):     # counting down
    print(i, end=' ')

# Output:
# 7-13-19-25-31-37-
# 10 8 6 4 2

n = int(input("Table of: "))
for i in range(1, 11):
    print(n, "x", i, "=", n * i)

# Sample run (the values after each prompt are typed by the user):
# Table of: 7
# 7 x 1 = 7
# 7 x 2 = 14
# 7 x 3 = 21
# 7 x 4 = 28
# 7 x 5 = 35
# 7 x 6 = 42
# 7 x 7 = 49
# 7 x 8 = 56
# 7 x 9 = 63
# 7 x 10 = 70

n = int(input("Enter N: "))
total = 0
for i in range(1, n + 1):
    total += i
print("Sum of 1 to", n, "=", total)

# Sample run (the values after each prompt are typed by the user):
# Enter N: 10
# Sum of 1 to 10 = 55

n = int(input("Enter a positive number: "))
fact = 1
for i in range(1, n + 1):
    fact *= i
print(n, "! =", fact)

# Sample run (the values after each prompt are typed by the user):
# Enter a positive number: 6
# 6 ! = 720

for i in range(5):
    num = int(input("Enter a number: "))
    if num % 2 == 0:          # % (remainder), not / (division)
        print("Even")
    else:
        print("Odd")          # indented inside else

# Sample run (the values after each prompt are typed by the user):
# Enter a number: 4
# Even
# Enter a number: 7
# Odd
# Enter a number: 10
# Even
# Enter a number: 13
# Odd
# Enter a number: 22
# Even

n = int(input("How many terms? "))
a, b = 0, 1
for i in range(n):
    print(a, end=" ")
    a, b = b, a + b

# Sample run (the values after each prompt are typed by the user):
# How many terms? 10
# 0 1 1 2 3 5 8 13 21 34

n = int(input("Enter a number: "))
if n <= 1:
    print(n, "is neither prime nor composite")
else:
    is_prime = True
    for i in range(2, n):
        if n % i == 0:
            is_prime = False
            break
    if is_prime:
        print(n, "is a prime number")
    else:
        print(n, "is a composite number")

# Sample run (the values after each prompt are typed by the user):
# Enter a number: 91
# 91 is a composite number

n = int(input("Enter a positive integer: "))
c = 0
for i in range(1, n + 1):
    if n % i == 0:
        c += 1
print(c)

# Sample run (the values after each prompt are typed by the user):
# Enter a positive integer: 12
# 6

n = int(input("Enter a number: "))
rev = 0
total = 0
while n > 0:
    digit = n % 10
    rev = rev * 10 + digit
    total += digit
    n = n // 10
print("Reverse:", rev)
print("Sum of digits:", total)

# Sample run (the values after each prompt are typed by the user):
# Enter a number: 4721
# Reverse: 1274
# Sum of digits: 14

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

# Palindrome
temp, rev = n, 0
while temp > 0:
    rev = rev * 10 + temp % 10
    temp //= 10
print("Palindrome:", rev == n)

# Armstrong
digits = len(str(n))
temp, total = n, 0
while temp > 0:
    total += (temp % 10) ** digits
    temp //= 10
print("Armstrong:", total == n)

# Perfect
factor_sum = 0
for i in range(1, n):
    if n % i == 0:
        factor_sum += i
print("Perfect:", factor_sum == n)

# Sample run (the values after each prompt are typed by the user):
# Enter a number: 153
# Palindrome: False
# Armstrong: True
# Perfect: False

a = int(input("First number: "))
b = int(input("Second number: "))
x, y = a, b
while y != 0:
    x, y = y, x % y
gcd = x
lcm = a * b // gcd
print("GCD =", gcd)
print("LCM =", lcm)

# Sample run (the values after each prompt are typed by the user):
# First number: 24
# Second number: 36
# GCD = 12
# LCM = 72

for i in range(1, 11):
    if i == 8:
        break          # stop at 8
    if i % 3 == 0:
        continue       # skip 3 and 6
    print(i, end=" ")

# Output:
# 1 2 4 5 7

n = 5
for i in range(1, n + 1):
    for j in range(i):
        print("*", end="")
    print()

# Output:
# *
# **
# ***
# ****
# *****

n = 5
for i in range(n, 0, -1):
    for j in range(1, i + 1):
        print(j, end="")
    print()

# Output:
# 12345
# 1234
# 123
# 12
# 1

n = 5
for i in range(1, n + 1):
    for j in range(i):
        print(chr(65 + j), end="")
    print()

# Output:
# A
# AB
# ABC
# ABCD
# ABCDE

x = int(input("Enter x: "))
n = int(input("Enter n: "))
total = 0
for i in range(n + 1):
    total += x ** i
print("Sum =", total)

# Sample run (the values after each prompt are typed by the user):
# Enter x: 2
# Enter n: 5
# Sum = 63

x = int(input("Enter x: "))
n = int(input("Enter n: "))
total = 0
for i in range(n + 1):
    total += (-1) ** i * x ** i
print("Sum =", total)

# Sample run (the values after each prompt are typed by the user):
# Enter x: 2
# Enter n: 5
# Sum = -21

x = float(input("Enter x: "))
n = int(input("Enter n: "))
total = 0
for i in range(1, n + 1):
    total += x ** i / i
print("Sum =", round(total, 4))

# Sample run (the values after each prompt are typed by the user):
# Enter x: 2
# Enter n: 4
# Sum = 10.6667

x = float(input("Enter x: "))
n = int(input("Enter n: "))
total = 0
fact = 1
for i in range(1, n + 1):
    fact *= i              # i!
    total += x ** i / fact
print("Sum =", round(total, 4))

# Sample run (the values after each prompt are typed by the user):
# Enter x: 2
# Enter n: 4
# Sum = 6.0

given = 123456
new = 0
while given:                  # runs while given is not 0
    if new % 2:               # new is odd
        new += given % 10
    else:                     # new is even
        new += given % 5
    print(new, end='-')
    given //= 10

# Output:
# 1-6-10-13-15-16-

import random

secret = random.randint(1, 20)
tries = 0
while True:
    guess = int(input("Guess (1-20): "))
    tries += 1
    if guess < secret:
        print("Too small")
    elif guess > secret:
        print("Too big")
    else:
        print("Correct! You took", tries, "tries")
        break

# One possible output (yours may differ):
# Guess (1-20): 10
# Too small
# Guess (1-20): 15
# Too big
# Guess (1-20): 12
# Too big
# Guess (1-20): 13
# Too big
# Guess (1-20): 14
# Too big
# Guess (1-20): 11
# Correct! You took 6 tries

s = "PYTHON"
print(s[0], s[3], s[-1])
for ch in s:
    print(ch, end=" ")
print()
for i in range(len(s)):
    print(i, s[i])

# Output:
# P H N
# P Y T H O N
# 0 P
# 1 Y
# 2 T
# 3 H
# 4 O
# 5 N

a = "Computer"
b = "Science"
print(a + " " + b)        # concatenation
print("Hi! " * 3)         # repetition
print("put" in a)         # membership
print(a[0:4])             # slicing: positions 0 to 3
print(a[::-1])            # reverse

# Output:
# Computer Science
# Hi! Hi! Hi!
# True
# Comp
# retupmoC

s = "the Truth"
print(s.upper())
print(s.lower())
print(s.capitalize())     # only the first letter capital
print(s.title())          # each word capital

# Output:
# THE TRUTH
# the truth
# The truth
# The Truth

print("Python".isalpha())
print("2024".isdigit())
print("Class12".isalnum())
print("   ".isspace())
print("Hello".isupper(), "hello".islower())
username = "admin_ravi"
print(username.startswith("admin"))
print("notes.txt".endswith(".txt"))

# Output:
# True
# True
# True
# True
# False True
# True
# True

game = 'Olympic2024'
print(game.index('c'))
s = "an apple. a toy."
print(s.find('a', 2))           # search from position 2
text = "Python Programming"
print(text.find("z"))           # -1: not found
print(text.replace("o", "0"))
print("This is his book".count("is"))
print("PYTHONPROGRAM".replace('PY', '#'))

# Output:
# 6
# 3
# -1
# Pyth0n Pr0gramming
# 3
# #THONPROGRAM

print("Paralympic Games".split("m"))
print("programming is amazing".split("m"))
print('War and Peace by Leo Tolstoy'.partition("by"))
l = "Python is fun".split()
print("-".join([l[0].upper(), l[1], l[2].capitalize()]))
print("   hello   ".strip(), "|", "   hello".lstrip(), "|", "hello   ".rstrip())

# Output:
# ['Paraly', 'pic Ga', 'es']
# ['progra', '', 'ing is a', 'azing']
# ('War and Peace ', 'by', ' Leo Tolstoy')
# PYTHON-is-Fun
# hello | hello | hello

myStr = "MISSISSIPPI"
print(myStr[:4] + "#" + myStr[-5:])
print("PythonProgram"[-1:2:-2])
pride = "#G20 Presidency"
print(pride[-2:2:-2])
s = "Soft Skills"
print(s[-3::-3])
text = "Drone Expo"
print(text[-2::-4])

# Output:
# MISS#SIPPI
# mroPo
# ceieP0
# lSf
# peD

s = input("Enter a string: ")
vowels = consonants = upper = lower = 0
for ch in s:
    if ch.isalpha():
        if ch in "aeiouAEIOU":
            vowels += 1
        else:
            consonants += 1
        if ch.isupper():
            upper += 1
        else:
            lower += 1
print("Vowels:", vowels)
print("Consonants:", consonants)
print("Uppercase:", upper)
print("Lowercase:", lower)

# Sample run (the values after each prompt are typed by the user):
# Enter a string: Hello World from CSIP12
# Vowels: 5
# Consonants: 13
# Uppercase: 6
# Lowercase: 12

s = input("Enter a string: ")
if s.lower() == s.lower()[::-1]:
    print(s, "is a palindrome")
else:
    print(s, "is not a palindrome")

result = ""
for ch in s:
    if ch.isupper():
        result += ch.lower()
    elif ch.islower():
        result += ch.upper()
    else:
        result += ch
print("Case converted:", result)

# Sample run (the values after each prompt are typed by the user):
# Enter a string: Madam
# Madam is a palindrome
# Case converted: mADAM

s = input("Enter a sentence: ")
words = s.split()
print("Number of words:", len(words))
longest = ""
for w in words:
    if len(w) > len(longest):
        longest = w
print("Longest word:", longest)

# Sample run (the values after each prompt are typed by the user):
# Enter a sentence: Practice makes a programmer perfect
# Number of words: 5
# Longest word: programmer

S = "Racecar Car Radar"
L = S.split()
for W in L:
    x = W.upper()
    if x == x[::-1]:
        for I in x:
            print(I, end="*")
    else:
        for I in W:
            print(I, end="#")
    print()

# Output:
# R*A*C*E*C*A*R*
# C#a#r#
# R*A*D*A*R*

Text1 = "IND-23"
Text2 = ""
I = 0
while I < len(Text1):
    if Text1[I] >= "0" and Text1[I] <= "9":
        Val = int(Text1[I])
        Val = Val + 1
        Text2 = Text2 + str(Val)
    elif Text1[I] >= "A" and Text1[I] <= "Z":
        Text2 = Text2 + (Text1[I + 1])
    else:
        Text2 = Text2 + "*"
    I += 1
print(Text2)

# Output:
# ND-*34

code = "gLaD5"
result = []
i = 0
while i < len(code):
    if code[i].isupper():
        result.append(code[i].lower())
    elif code[i].isdigit():
        result.append(int(code[i]) * 2)
    else:
        result.append("#")
    i += 1
print(result)

# Output:
# ['#', 'l', '#', 'd', 10]

s = input("Enter a string: ")
result = ""
for ch in s:
    if ch.lower() not in "aeiou":
        result += ch
print("Without vowels:", result)

# Sample run (the values after each prompt are typed by the user):
# Enter a string: Education is important
# Without vowels: dctn s mprtnt

marks = [78, 92, 85, 64, 90]
print(marks)
print("First:", marks[0], " Last:", marks[-1])
marks[1] = 95            # lists can be changed
for m in marks:
    print(m, end=" ")
print()
print("Length:", len(marks))

# Output:
# [78, 92, 85, 64, 90]
# First: 78  Last: 90
# 78 95 85 64 90
# Length: 5

a = [1, 2, 3]
b = [4, 5]
print(a + b)
print(a * 2)
print(3 in a, 7 in a)
L = [10, 20, 30, 40, 50, 60]
print(L[1:4], L[::2], L[::-1])

# Output:
# [1, 2, 3, 4, 5]
# [1, 2, 3, 1, 2, 3]
# True False
# [20, 30, 40] [10, 30, 50] [60, 50, 40, 30, 20, 10]

L1 = [10, 20, 25, 30]
L1.insert(1, 15)        # at position 1
print(L1)
L1.append(40)           # at the end
L1.extend([50, 60])     # many at the end
print(L1)
L1.remove(25)           # by value
print(L1.pop())         # removes and returns the last item
print(L1.pop(0))        # removes position 0
print(L1)

# Output:
# [10, 15, 20, 25, 30]
# [10, 15, 20, 25, 30, 40, 50, 60]
# 60
# 10
# [15, 20, 30, 40, 50]

nums = [45, 12, 78, 34, 89, 23]
print("Maximum:", max(nums))
print("Minimum:", min(nums))
print("Mean:", sum(nums) / len(nums))

# Output:
# Maximum: 89
# Minimum: 12
# Mean: 46.833333333333336

L = [40, 10, 30, 20]
L1 = sorted(L)              # new list, L unchanged
print(L, L1)
L.sort(reverse=True)        # descending, changes L
print(L)
L.reverse()
print(L)

# Output:
# [40, 10, 30, 20] [10, 20, 30, 40]
# [40, 30, 20, 10]
# [10, 20, 30, 40]

P = [3, 5, 7, 4]
P.insert(2, 3)
P.extend([10, 6])
print(P)
print(P.index(7))
print(P[::2])

# Output:
# [3, 5, 3, 7, 4, 10, 6]
# 3
# [3, 3, 4, 6]

L = eval(input("Enter a list, e.g. [4, 8, 2]: "))
x = int(input("Element to search: "))
found = False
for i in range(len(L)):
    if L[i] == x:
        print(x, "found at position", i)
        found = True
        break
if not found:
    print(x, "is not in the list")

# Sample run (the values after each prompt are typed by the user):
# Enter a list, e.g. [4, 8, 2]: [12, 45, 7, 33, 90]
# Element to search: 33
# 33 found at position 3

L = [2, 7, 9, 9, 2, 5, 9]
done = []
for x in L:
    if x not in done:
        print(x, "appears", L.count(x), "times")
        done.append(x)
print("The largest appears", L.count(max(L)), "times")

# Output:
# 2 appears 2 times
# 7 appears 1 times
# 9 appears 3 times
# 5 appears 1 times
# The largest appears 3 times

L = eval(input("Enter a list: "))
for i in range(0, len(L) - 1, 2):
    L[i], L[i + 1] = L[i + 1], L[i]
print("After swapping:", L)

# Sample run (the values after each prompt are typed by the user):
# Enter a list: [1, 2, 3, 4, 5, 6, 7]
# After swapping: [2, 1, 4, 3, 6, 5, 7]

words = ["Class Test", "Term Exams", "Pre-board Exam", "Board Exam"]
L = len(words)
for i in range(L - 1, -1, -1):
    print(words[i], end=" ")

# Output:
# Board Exam Pre-board Exam Term Exams Class Test

students = [["Riya", 88], ["Aman", 75], ["Sara", 93]]
print(students[1])          # ['Aman', 75]
print(students[2][0])       # Sara
for s in students:
    print(s[0], "scored", s[1])

# Output:
# ['Aman', 75]
# Sara
# Riya scored 88
# Aman scored 75
# Sara scored 93

event = "G20 Presidency@2023"
L = event.split(' ')
print(L[::-2])
p = list("Session 2024-25")
print(p[10:20:])
L = ["India", "Incredible", "Bharat"]
print(L[1][0] + L[2][-1])

# Output:
# ['Presidency@2023']
# ['2', '4', '-', '2', '5']
# It

given = "Gold-24Medals"
new = []
for ch in given[1:-1]:        # leave out the first and last character
    if ch.isupper():
        new.reverse()
    elif ch not in new:
        new.append(ch)
    elif ch in new:
        new.pop()
print(new)

# Output:
# ['4', '2', '-', 'd', 'l', 'o']

L = [45, 78, 12, 90, 67, 90]
first = second = None
for x in L:
    if first is None or x > first:
        second = first
        first = x
    elif x != first and (second is None or x > second):
        second = x
print("Largest:", first, " Second largest:", second)

# Output:
# Largest: 90  Second largest: 78

L = [3, 5, 3, 7, 5, 9, 3]
unique = []
for x in L:
    if x not in unique:
        unique.append(x)
print(unique)

# Output:
# [3, 5, 7, 9]

t = (10, 20, 30, 40)
print(t[0], t[-1], t[1:3])
single = (5,)              # comma makes it a tuple
print(type(single), type((5)))
t2 = tuple("tuple")        # from a string
print(t2)

# Output:
# 10 40 (20, 30)
# <class 'tuple'> <class 'int'>
# ('t', 'u', 'p', 'l', 'e')

t = (10, 20, 30)
# t[0] = 5     -> TypeError: 'tuple' object does not support item assignment
t = (5,) + t[1:]           # make a new tuple instead
print(t)

# t + [4, 5]   -> TypeError: a tuple cannot be joined with a list
print(t + (4, 5))          # tuple + tuple is fine

# Output:
# (5, 20, 30)
# (5, 20, 30, 4, 5)

t = (4, 9, 2, 9, 7, 9)
print(len(t), t.count(9), t.index(2))
print(min(t), max(t), sum(t))
print(sorted(t))           # gives a list

# Output:
# 6 3 2
# 2 9 40
# [2, 4, 7, 9, 9, 9]

student = ("Riya", 17, ("Maths", "CS"))
name, age, subjects = student      # tuple assignment
print(name, age)
print(subjects[1])
print(student[2][0])               # nested tuple

# Output:
# Riya 17
# CS
# Maths

t = tuple('tuple')
t2 = t[2],
t += t2
print(t)

tuple1 = (1, 2, 3)
tuple2 = tuple1
tuple1 += (4,)
print(tuple1 == tuple2)

# Output:
# ('t', 'u', 'p', 'l', 'e', 'p')
# False

t = (56, 23, 89, 12, 45)
print("Largest:", max(t))
print("Smallest:", min(t))
print("Mean:", sum(t) / len(t))

# Output:
# Largest: 89
# Smallest: 12
# Mean: 45.0

t = (5, 8, 3, 8, 1, 8)
x = int(input("Element to search: "))
if x in t:
    print(x, "is at position", t.index(x), "and appears", t.count(x), "times")
else:
    print(x, "not found")

# Sample run (the values after each prompt are typed by the user):
# Element to search: 8
# 8 is at position 1 and appears 3 times

subject = ("English", "Maths", "Physics", "CS")
subject_list = list(subject)
subject_list.pop()            # delete the last element
print(subject_list)
subject = tuple(subject_list)
print(subject)

# Output:
# ['English', 'Maths', 'Physics']
# ('English', 'Maths', 'Physics')

student = {"name": "Riya", "class": 11, "marks": 88}
print(student["name"])
student["marks"] = 92          # change
student["city"] = "Delhi"      # add
print(student)
print(len(student))

# Output:
# Riya
# {'name': 'Riya', 'class': 11, 'marks': 92, 'city': 'Delhi'}
# 4

D = {'S01': 95, 'S02': 96, 'S03': 88}
for I in D:
    print(I, end='#')
print()
print(list(D.keys()))
print(list(D.values()))
for k, v in D.items():
    print(k, "->", v)

# Output:
# S01#S02#S03#
# ['S01', 'S02', 'S03']
# [95, 96, 88]
# S01 -> 95
# S02 -> 96
# S03 -> 88

my_dict = {"name": "Alicia", "age": 27, "city": "DELHI"}
print(my_dict.get("profession", "Not Specified"))
print(my_dict.get("age"))
Dl = {"Pen": 12, "Pencil": 6, "Scale": 5, "InkPen": 20}
print(12 in Dl)              # False: 12 is a value, not a key
print("Pen" in Dl)
print(12 in Dl.values())

# Output:
# Not Specified
# 27
# False
# True
# True

Students = {"ANITA": 90, "NISHA": 76, "ASHA": 92, "RAJ": 81}
Students.pop("NISHA")
print(Students)
del Students["ASHA"]
print(Students)
print(Students.popitem())
Students.clear()
print(Students)

# Output:
# {'ANITA': 90, 'ASHA': 92, 'RAJ': 81}
# {'ANITA': 90, 'RAJ': 81}
# ('RAJ', 81)
# {}

D1 = {"a": 1, "b": 2}
D2 = {"b": 20, "c": 30}
D1.update(D2)                     # add/replace from D2
print(D1)
print(D1.setdefault("RNo", 12))   # adds RNo: 12 only if it is missing
print(D1.setdefault("a", 99))     # key exists: returns its value
print(D1)
marks = dict.fromkeys(["Riya", "Aman"], 0)
print(marks)
backup = D1.copy()
print(backup == D1, backup is D1)
print(tuple(D2.keys()))

# Output:
# {'a': 1, 'b': 20, 'c': 30}
# 12
# 1
# {'a': 1, 'b': 20, 'c': 30, 'RNo': 12}
# {'Riya': 0, 'Aman': 0}
# True False
# ('b', 'c')

s = input("Enter a string: ")
freq = {}
for ch in s:
    if ch in freq:
        freq[ch] += 1
    else:
        freq[ch] = 1
for ch in freq:
    print(repr(ch), ":", freq[ch])

# Sample run (the values after each prompt are typed by the user):
# Enter a string: banana bread
# 'b' : 2
# 'a' : 4
# 'n' : 2
# ' ' : 1
# 'r' : 1
# 'e' : 1
# 'd' : 1

emp = {}
n = int(input("Number of employees: "))
for i in range(n):
    name = input("Name: ")
    salary = int(input("Salary: "))
    emp[name] = salary
print(emp)
name = input("Whose salary? ")
print(name, "earns", emp.get(name, "- not found"))

# Sample run (the values after each prompt are typed by the user):
# Number of employees: 3
# Name: Kiran
# Salary: 45000
# Name: Dev
# Salary: 52000
# Name: Meera
# Salary: 61000
# {'Kiran': 45000, 'Dev': 52000, 'Meera': 61000}
# Whose salary? Dev
# Dev earns 52000

n = int(input("Number of students: "))
result = {}
for i in range(n):
    roll = int(input("Roll number: "))
    name = input("Name: ")
    marks = int(input("Marks: "))
    result[roll] = [name, marks]

print("Students with marks above 75:")
for roll in result:
    if result[roll][1] > 75:
        print(result[roll][0])

# Sample run (the values after each prompt are typed by the user):
# Number of students: 3
# Roll number: 1
# Name: Riya
# Marks: 88
# Roll number: 2
# Name: Aman
# Marks: 72
# Roll number: 3
# Name: Sara
# Marks: 91
# Students with marks above 75:
# Riya
# Sara

LS = ["HIMALAYA", "NILGIRI", "ALASKA", "ALPS"]
D = {}
for S in LS:
    if len(S) % 4 == 0:
        D[S] = len(S)
for K in D:
    print(K, D[K], sep="#")

# Output:
# HIMALAYA#8
# ALPS#4

S = "LOST"
L = [10, 21, 33, 4]
D = {}
for I in range(len(S)):
    if I % 2 == 0:
        D[L.pop()] = S[I]
    else:
        D[L.pop()] = I + 3
for K, V in D.items():
    print(K, V, sep="*")

# Output:
# 4*L
# 33*4
# 21*S
# 10*6

emp = {"Arv": (85000, 90000), "Ria": (78000, 88000),
       "Jay": (72000, 80000), "Tia": (80000, 70000)}
selected = []
for name in emp:
    salary = emp[name]
    average = (salary[0] + salary[1]) / 2
    if average > 80000:
        selected.append(name)
print(selected)

# Output:
# ['Arv', 'Ria']

marks = {"Riya": 88, "Aman": 75, "Sara": 93, "Kabir": 67}
topper = max(marks, key=marks.get)
print("Topper:", topper, marks[topper])
print("Names in order:", sorted(marks))
print("Lowest marks:", min(marks.values()))

# Output:
# Topper: Sara 93
# Names in order: ['Aman', 'Kabir', 'Riya', 'Sara']
# Lowest marks: 67

import math

print(math.pi, math.e)
print(math.sqrt(81))
print(math.pow(2, 5))
print(math.ceil(4.2), math.floor(4.8))
print(math.fabs(-7.5))
r = 7
print("Area of circle:", round(math.pi * r * r, 2))

# Output:
# 3.141592653589793 2.718281828459045
# 9.0
# 32.0
# 5 4
# 7.5
# Area of circle: 153.94

from math import sqrt, pi
from statistics import mean

print(sqrt(144))
print(round(2 * pi * 5, 2))
print(mean([10, 20, 30]))

# Output:
# 12.0
# 31.42
# 20

import math

angle = math.radians(30)
print(round(math.sin(angle), 2))
print(round(math.cos(math.radians(60)), 2))
print(round(math.tan(math.radians(45)), 2))

# Output:
# 0.5
# 0.5
# 1.0

import statistics

studentAge = [15, 16, 16, 17, 16, 15, 18]
print(statistics.mean(studentAge))
print(statistics.median(studentAge))
print(statistics.mode(studentAge))

# Output:
# 16.142857142857142
# 16
# 16

import random

print(random.random())
print(random.randint(1, 6))        # 1 to 6
print(random.randrange(1, 6))      # 1 to 5
print(random.randrange(0, 20, 5))  # 0, 5, 10 or 15

# One possible output (yours may differ):
# 0.32383276483316237
# 2
# 4
# 0

import random

Signal = ['RED', 'YELLOW', 'GREEN']
for K in range(2, 0, -1):
    R = random.randrange(K)        # K=2: 0 or 1, then K=1: only 0
    print(Signal[R], end='#')
print()

a = [1, 2, 3, 4, 5, 6]
for i in range(4):
    j = random.randrange(i, 5)     # i to 4
    print(a[j], end='-')

# One possible output (yours may differ):
# YELLOW#RED#
# 4-2-3-4-

import random

L = [10, 30, 50, 70]
Lower = random.randint(2, 2)     # always 2
Upper = random.randint(2, 3)     # 2 or 3
for K in range(Lower, Upper + 1):
    print(L[K], end="@")
print()

games = {0: "Chess", 1: "Scrabble", 2: "Sudoku", 3: "Tic-Tac-Toe", 4: "Puzzle"}
start_key = random.randint(1, 2)
end_key = random.randrange(3, 4)   # always 3
for k in range(start_key, end_key + 1):
    print(games[k], end="@@")

# One possible output (yours may differ):
# 50@
# Sudoku@@Tic-Tac-Toe@@

import random

otp = ""
for i in range(6):
    otp += str(random.randint(0, 9))
print("Your OTP is", otp)

# One possible output (yours may differ):
# Your OTP is 526018