Important Programs (Practical File)

# 1. Menu-driven program using user-defined functions
def factorial(n):
    f = 1
    for i in range(2, n + 1):
        f *= i
    return f
def is_prime(n):
    if n < 2:
        return False
    for i in range(2, int(n ** 0.5) + 1):
        if n % i == 0:
            return False
    return True
def fibonacci(n):
    a, b, out = 0, 1, []
    for _ in range(n):
        out.append(a); a, b = b, a + b
    return out
ch = int(input('1.Factorial 2.Prime 3.Fibonacci : '))
n = int(input('Enter n: '))
if ch == 1:
    print('Factorial =', factorial(n))
elif ch == 2:
    print(n, 'is prime' if is_prime(n) else 'is not prime')
else:
    print(fibonacci(n))

# 2. Create a text file, then count vowels, consonants, uppercase, lowercase
with open('story.txt', 'w') as f:
    f.write('Python Is Easy.\nPractice Daily And Enjoy Coding!\nWe Love It.\n')
v = c = up = lo = 0
with open('story.txt') as f:
    for ch in f.read():
        if ch.isalpha():
            if ch.lower() in 'aeiou': v += 1
            else: c += 1
            if ch.isupper(): up += 1
            else: lo += 1
print('Vowels:', v, 'Consonants:', c, 'Upper:', up, 'Lower:', lo)

# 3. Read a text file line by line and display each word separated by '#'
with open('story.txt') as f:
    for line in f:
        print('#'.join(line.split()))

# 4. Copy lines that do NOT contain 'a' into another file
with open('story.txt') as src, open('no_a.txt', 'w') as dst:
    for line in src:
        if 'a' not in line.lower():
            dst.write(line)
with open('no_a.txt') as f:
    print('No a  :', f.read(), end='')
with open('story.txt') as src, open('with_a.txt', 'w') as dst:
    dst.writelines(l for l in src if 'a' in l.lower())
with open('with_a.txt') as f:
    print('With a:', f.read(), end='')

# 5. Binary file: store [roll, name] records and search by roll number
import pickle
with open('stud.dat', 'wb') as f:
    for rec in [[1, 'Asha'], [2, 'Ravi'], [3, 'Neha']]:
        pickle.dump(rec, f)
def search(roll):
    with open('stud.dat', 'rb') as f:
        try:
            while True:
                r = pickle.load(f)
                if r[0] == roll:
                    return r[1]
        except EOFError:
            return 'Roll number not found'
print(search(2))
print(search(9))

# 6. Binary file: update marks of a given roll number
import pickle
with open('marks.dat', 'wb') as f:
    pickle.dump([[1, 'Asha', 81], [2, 'Ravi', 67], [3, 'Neha', 74]], f)
def update(roll, new):
    with open('marks.dat', 'rb') as f:
        data = pickle.load(f)
    found = False
    for r in data:
        if r[0] == roll:
            r[2] = new; found = True
    with open('marks.dat', 'wb') as f:
        pickle.dump(data, f)
    return found
print('Updated:', update(2, 72))
with open('marks.dat', 'rb') as f:
    print(pickle.load(f))

# 7. Random number generator that simulates a dice
import random
random.seed(7)                      # same output every run (for the practical file)
rolls = [random.randint(1, 6) for _ in range(10)]
print('Rolls:', rolls)
print('Sixes:', rolls.count(6))

# 8. CSV file: store user-id and password, then search a user-id
import csv
with open('users.csv', 'w', newline='') as f:
    w = csv.writer(f)
    w.writerow(['UserID', 'Password'])
    w.writerows([['asha01', 'Sun@123'], ['ravi_k', 'Moon#45'], ['neha.s', 'Star$78']])
def get_password(uid):
    with open('users.csv', newline='') as f:
        r = csv.reader(f); next(r)
        for u, p in r:
            if u == uid:
                return p
    return 'User not found'
print(get_password('ravi_k'))
print(get_password('zoya'))

# 9. Stack implementation using a list (push, pop, peek, display)
stack = []
def push(x): stack.append(x)
def pop(): return stack.pop() if stack else 'Underflow'
def peek(): return stack[-1] if stack else 'Underflow'
for x in [10, 20, 30]:
    push(x)
print('Stack (top first):', stack[::-1])
print('Peek:', peek(), '| Pop:', pop(), '| Now:', stack)
print(pop(), pop(), pop())

# 10. Bubble sort and binary search on a list of numbers
def bubble(a):
    for i in range(len(a) - 1):
        for j in range(len(a) - 1 - i):
            if a[j] > a[j + 1]:
                a[j], a[j + 1] = a[j + 1], a[j]
    return a
def bsearch(a, key):
    lo, hi = 0, len(a) - 1
    while lo <= hi:
        mid = (lo + hi) // 2
        if a[mid] == key: return mid
        if a[mid] < key: lo = mid + 1
        else: hi = mid - 1
    return -1
nums = bubble([34, 7, 23, 32, 5, 62])
print('Sorted:', nums)
print('23 at index', bsearch(nums, 23))

# 11. Count occurrences of each word in a text file using a dictionary
with open('para.txt', 'w') as f:
    f.write('the cat and the hat and the bat')
freq = {}
with open('para.txt') as f:
    for w in f.read().split():
        freq[w] = freq.get(w, 0) + 1
for w in sorted(freq, key=freq.get, reverse=True):
    print(w, freq[w])

# 12. Exception handling while dividing user values
try:
    a = int(input('a: '))
    b = int(input('b: '))
    print('a / b =', a / b)
except ZeroDivisionError:
    print('Cannot divide by zero')
except ValueError:
    print('Please enter whole numbers only')
finally:
    print('Program over')