Python Tutorials

Different Exception Types in Python

Exception Types in Python

ZeroDivisionError

When you try to divide a number by zero (0) in Python, you will get a ZeroDivisionError.

In Python, division by zero (0) is not allowed.

Example

number = 20
division = number / 0
print(division)

division = number / 0
ZeroDivisionError: division by zero

In the above example, we tried to divide a number by zero (0), but we got zero division by error.

To catch zero division by error exception use, try-except block.

Example

try:
    number = 20
    division = number / 0
    print(division)
except ZeroDivisionError as e:
    print("Exception:", e)

Exception: division by zero

TypeError

A TypeError occurs when an operation is performed on an object of an inappropriate type.

This can happen when you try to perform arithmetic or logical operations on incompatible data types.

Example

number_1 = 20
number_2 = "2"
print(number_1 + number_2)

print(number_1 + number_2)
TypeError: unsupported operand type(s) for +: 'int' and 'str'

This error occurs because Python cannot add an integer to a string.

To catch this exception, use try-except block while adding numbers.

Example

try:

    number_1 = 20
    number_2 = "2"
    print(number_1 + number_2)

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

Exception: unsupported operand type(s) for +: 'int' and 'str'

NameError

A NameError occurs when you try to use a variable that has not been defined.

This can happen if you have misspelled the variable name, or if you have not assigned a value to the variable before trying to use it.

Example

print(number_1)

NameError: name 'number_1' is not defined

In the above example, we have not defined the number_1 variable, so we got a NameError exception.

To avoid NameError, you should always make sure that you have defined a variable before trying to use it.

Also, make sure that you have spelt the variable name correctly.

Example

try:

  print(number_1)

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

Exception: name 'number_1' is not defined

IndexError

An index error in Python occurs when you try to access an element of a list, tuple, or string using an invalid index.

The index is the number that identifies the position of an element in a sequence.

In Python, indexing starts from 0, so the first element in a sequence has an index of 0, the second element has an index of 1, and so on.

Example

colors_list = ["Red", "Blue", "Green"]
print(colors_list[3])

IndexError: list index out of range

In the above example, we tried to access the 3rd index item, but the list doesn't have an index 3rd item, so we got the IndexError.

Handle IndexError using try-except block.

Example

try:

  colors_list = ["Red", "Blue", "Green"]
  print(colors_list[3])

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

Exception: list index out of range

AssertionError

An AssertionError in Python is raised when an assert statement evaluates to False.

The assert statement is a debugging tool that allows you to check for certain conditions in your code and raise an exception if those conditions are not met.

This can be useful for catching errors early on before they cause your program to crash.

Example

assert 10 > 20

assert 10 > 20
AssertionError

AssertionError can be handled using a try-except block.

Example

try:

  assert 10 > 20

except AssertionError as e:
  print("Exception: Assertion error")

Exception: Assertion error