Python Exception Handling

1) Basic Try/Except

Ask the user to input two numbers and perform division inside a try. Catch any exception and print:

An error occurred.

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2) Catch ZeroDivisionError Only

Prompt for two integers and divide them. Handle only ZeroDivisionError with a message:

Error: You cannot divide by zero!

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3) Catch ValueError

Ask the user to input an integer. Wrap in try, catch ValueError if input isn’t numeric.

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4) Division with Multiple Except

Prompt for numbers and divide. Use separate except blocks for:

• ValueError

• ZeroDivisionError

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5) Safe Input Loop

Keep asking for a valid integer until the user enters one (loop + exception).

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6) Catch IndexError

Given list [10,20,30], ask for index and catch IndexError if input is out of bounds.

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7) Catch KeyError

Given dict {"a":1, "b":2}, ask user for a key and catch KeyError if not found.

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8) Use Else Block

In a try/except, add else: to print:

No errors occurred!

when division succeeds.

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9) Use Finally Block

Open a file that may not exist (enter filename). Use finally: to always print:

Finished checking file.

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10) Nested Try

Inside one try, convert input to int, then inside another try divide numbers. Handle errors separately.

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11) Catch TypeError

Perform an invalid operation like 1 + "a" inside try and catch TypeError.

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12) Raise Custom Error

Ask for age. If age < 0, raise ValueError("Age cannot be negative") inside a try.

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13) Validate Range

Ask for a number 1–10. If out of range, raise and catch a ValueError.

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14) Read File Safely

Ask for a filename and use try to open + read it; catch exceptions if it fails.

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15) Continue on Error

Loop reading 5 integers from user. If one input causes ValueError, print message and continue the loop.

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16) Log Exception Message

Catch an exception and print its error message using the exception object.

Example:

except Exception as e:
    print("Error:", e)

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17) Validate Numeric CSV

Read a CSV file and convert a column to integers inside try/except to skip invalid rows.

(Dummy CSV like scores.csv with some non-numeric values.)

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18) Cleanup with Finally

Open and read a file; in finally, close the file if it was successfully opened.

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19) Safe Dictionary Access

Use try to access a dictionary value; in except print "Key not found".

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20) Function with Exception Handling

Write a function safe_divide(a, b) that returns division result; handle errors with try inside the function and return "Error" on failure.

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📌 Concepts Practiced

Concept	Example
Basic try/except	Assignments 1,2,3
Multiple excepts	4,6,7
else block	8
finally block	9,18
Raising exceptions	12,13
Handling exceptions in loops	15
Error messages	16

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💡 Starter Template

try:
    x = int(input("Enter a number: "))
    y = int(input("Enter another number: "))
    print("Result:", x / y)
except ZeroDivisionError:
    print("Cannot divide by zero!")
except ValueError:
    print("Invalid input!")
else:
    print("Successful operation!")
finally:
    print("Done.")

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canvil: 333f6c7d-6876-4f7e-b6ad-1bdb2233f5c1