Concrete Exceptions in Python

In Python, exceptions are a way of handling errors that occur during the execution of the program. When an error occurs Python raises an exception that can be caught and handled by the programmer to prevent the program from crashing. In this article, we will see about concrete exceptions in Python in detail with the help of examples.

Concrete Exceptions in Python

Below are some examples of common concrete exceptions in Python:

• Exception NameError
• Exception TypeError
• Exception IndexError
• Exception IndentationError
• Exception ZeroDivisionError
• Exception FileNotFoundError

Exception NameError

A NameError occurs when a name used in code is not found in local or global scope. This can happen when trying to the access a variable that has not been defined. In this example, the variable x is not defined before it is used in print statement resulting in the NameError.

Python3

# Example of NameError
print(x)

Output:

Hangup (SIGHUP)
Traceback (most recent call last):
  File "Solution.py", line 2, in <module>
    print(x)
NameError: name 'x' is not defined

Exception TypeError

A TypeError occurs when an operation or function is applied to an object of the inappropriate type. This can happen when performing the unsupported operations on the different data types. In this example, the + operator is used to the concatenate a string (x) and an integer (y) resulting in the TypeError.

Python3

# Example of TypeError
x = "Hello"
y = 5
result = x + y

Output:

Hangup (SIGHUP)
Traceback (most recent call last):
  File "Solution.py", line 4, in <module>
    result = x + y
TypeError: cannot concatenate 'str' and 'int' objects

Exception IndexError

An IndexError occurs when trying to the access an index that is out of range for given sequence. In this example, the index 3 is out of range for list my_list, which only has elements at indices 0, 1 and 2.

Python3

# Example of IndexError
my_list = [1, 2, 3]
print(my_list[3])

Output:

Hangup (SIGHUP)
Traceback (most recent call last):
  File "Solution.py", line 3, in <module>
    print(my_list[3])
IndexError: list index out of range

Exception IndentationError

An Indentation Error occurs in Python when incorrect indentation is used. Python relies on proper indentation to structure code. In the given example, an Indentation Error occurs because the code following the for loop is not properly indented, violating Python’s indentation rules.

Python3

x = 5
for i in range(x):
print(i)

Output

Hangup (SIGHUP)
  File "Solution.py", line 3
    print(i)
        ^
IndentationError: expected an indented block

Exception ZeroDivisionError

A ZeroDivisionError occurs when trying to the divide a number by zero. In this example, division by the zero is attempted resulting in the ZeroDivisionError.

Python3

# Example of ZeroDivisionError
result = 10 / 0

Output:

Hangup (SIGHUP)
Traceback (most recent call last):
  File "Solution.py", line 2, in <module>
    result = 10 / 0
ZeroDivisionError: integer division or modulo by zero

Exception FileNotFoundError

A FileNotFoundError occurs when trying to the access a file that does not exist. In this example, the file “nonexistent_file.txt” does not exist causing a FileNotFoundError when attempting to open it.

Python3

# Example of FileNotFoundError
with open("nonexistent_file.txt", "r") as file:
    contents = file.read()

Output:

FileNotFoundError: [Errno 2] No such file or directory: 'nonexistent_file.txt