⚠️ Exception Handling

Last Updated: 06 Sept 2025

  • Exception = error that happens while running a program.
  • Without handling → program crashes.
  • With handling → program catches error and continues safely.

✏ Basic try-except

We use try and except block.

try:
    x = 10 / 0   # division by zero
except ZeroDivisionError:
    print("Cannot divide by zero!")

👉 Here, instead of crashing, it prints message.

Multiple except Blocks

a=10
b=2

try:
    res=a/b
    print(res)
except ZeroDivisionError:
    print("Cannot divide by zero!")
except TypeError:
    print("Type error")
except:
    print("Any error")

Catching Any Exception

try:
    result = 10 / 0
except Exception as e:
    print("Error happened:", e)

👉 Exception as e gives the error message.

⚙ else with try-except

If there is no error, else block is executed.

try:
    x = 5 / 1
except ZeroDivisionError:
    print("Divide by zero error")
else:
    print("Division successful:", x)

🧹 finally Block

finally block is always executed.Either error occurs or not.

a=10
b=2

try:
    res=a/b
except ZeroDivisionError:
    print("error")
except:
    print("Any error")
else:
    print(res)
finally:
    print("Always RUN")

Custom Exceptions

We can raise our own exceptions using raise.

def check_age(age):
    if age < 18:
        raise ValueError("Age must be 18 or above")
    print("Access granted")

try:
    check_age(15)
except ValueError as e:
    print("Error:", e)

👉 Here, we raise error if age is less than 18.

💡 Quick Practice

  • Write a program to divide two numbers using try-except block.
  • Exercises
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