10 Important basic python codes

 

1. Hello World Program

print("Hello, World!")

Explanation:

• print() is used to display output.
• "Hello, World!" is a string (text inside quotes).
• This is the first program to check if Python is working.

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2. Add Two Numbers

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

Explanation:

• input() takes user input (as string).
• int() converts input into integer.
• a + b adds both numbers.
• print() displays the result.

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3. Check Even or Odd

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

if num % 2 == 0:
    print("Even")
else:
    print("Odd")

Explanation:

• % is modulus (remainder operator).
• If a number divided by 2 gives remainder 0, it's even.
• if-else is used for decision making.

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4. Largest of Three Numbers

a = int(input("Enter first number: "))
b = int(input("Enter second number: "))
c = int(input("Enter third number: "))

if a >= b and a >= c:
    print("Largest:", a)
elif b >= a and b >= c:
    print("Largest:", b)
else:
    print("Largest:", c)

Explanation:

• and checks multiple conditions.
• First condition checks if a is largest.
• elif checks second condition.
• else handles the remaining case.

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5. Simple Calculator

a = float(input("Enter first number: "))
b = float(input("Enter second number: "))
op = input("Enter operation (+, -, *, /): ")

if op == "+":
    print(a + b)
elif op == "-":
    print(a - b)
elif op == "*":
    print(a * b)
elif op == "/":
    print(a / b)
else:
    print("Invalid operation")

Explanation:

• float() allows decimal numbers.
• op stores the operation symbol.
• Based on the symbol, different operations are performed.

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6. Factorial of a Number

num = int(input("Enter a number: "))
fact = 1

for i in range(1, num + 1):
    fact *= i

print("Factorial:", fact)

Explanation:

• Factorial = 1 × 2 × 3 × ... × n
• range(1, num+1) loops from 1 to num.
• fact *= i means fact = fact * i.

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7. Multiplication Table

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

for i in range(1, 11):
    print(num, "x", i, "=", num * i)

Explanation:

• Loop runs from 1 to 10.
• Each time it multiplies num * i.

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8. Reverse a String

text = input("Enter a string: ")
print("Reversed:", text[::-1])

Explanation:

• [::-1] is slicing.
• It reverses the string.
• Very powerful Python shortcut.

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9. Count Vowels

text = input("Enter a string: ")
vowels = "aeiouAEIOU"
count = 0

for char in text:
    if char in vowels:
        count += 1

print("Vowel count:", count)

Explanation:

• Loop checks each character.
• if char in vowels checks if it is a vowel.
• count += 1 increases counter.

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10. Check Prime Number

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

if num > 1:
    for i in range(2, num):
        if num % i == 0:
            print("Not Prime")
            break
    else:
        print("Prime")
else:
    print("Not Prime")

Explanation:

• Prime numbers are divisible only by 1 and itself.
• Loop checks divisibility from 2 to num-1.
• break stops loop if divisor found.
• else runs only if loop completes fully.