Python Indentationerror: Expected An Indented Block

Python’s elegant and readable syntax relies heavily on indentation to define code blocks. However, developers may encounter challenges, notably the “IndentationError: Expected an Indented Block.” This error occurs when Python expects an indented block of code following a statement but encounters an issue with the indentation structure. In this article, we will explore the nature of this error, delve into common reasons behind its occurrence, and provide practical solutions for resolution.

What is “IndentationError: Expected an Indented Block” Error in Python?

The “IndentationError: Expected an Indented Block” is a Python error that arises when the interpreter encounters a statement that should be followed by an indented block, but no such block is provided. Python relies on indentation to determine the structure of code blocks, making it a fundamental aspect of the language’s syntax.

Reasons for “IndentationError: Expected an Indented Block” In Python

Below are some of the following reasons for this IndentationError: Expected an Indented Block error in Python:

• Missing Indentation
• Inconsistent Indentation
• Misplacement of Colons

Missing Indentation

One of the most common reasons for this error is omitting the required indentation after a statement that typically signifies the beginning of a code block, such as after an “if,” “else,” or “for” statement.

Python3

if True:
print("IndentationError expected.")

Output:

Hangup (SIGHUP)
  File "Solution.py", line 2
    print("IndentationError expected.")
        ^
IndentationError: expected an indented block

Inconsistent Indentation

Python enforces consistent indentation within the same block of code. Mixing spaces and tabs or using varying indentation levels can trigger the “IndentationError: Expected an Indented Block.”

Python3

if True:
    print("Indented with spaces.")
    else:
        print("Indented with tabs - IndentationError expected.")

Output:

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

Misplacement of Colons

Colons (:) are used to indicate the start of an indented block. Forgetting to place a colon at the end of a statement that requires indentation can lead to this error.

Python3

if True:
print("Missing colon - IndentationError expected.")

Output:

Hangup (SIGHUP)
  File "Solution.py", line 2
    print("Missing colon - IndentationError expected.")
        ^
IndentationError: expected an indented block

Solution for “IndentationError: Expected an Indented Block” In Python

Below are some of the solution for IndentationError: Expected an Indented Block in Python:

• Ensure Proper Indentation
• Check for Mixing Spaces & Tabs
• Verify Placement of Colons

Ensure Proper Indentation

Verify that the code has the correct indentation after statements like “if,” “else,” or “for.” Python conventionally uses four spaces for each level of indentation, but consistency is key.

Python3

condition = True

if condition:
    print("Code block executed.")

Output

Code block executed.

Check for Mixing Spaces and Tabs

Avoid mixing spaces and tabs for indentation within the same code block. Consistently use either spaces or tabs throughout the entire script to prevent indentation conflicts.

Python3

condition = True

if condition:
    print("Indented with spaces.")
else:
    print("Indented with tabs.")  # Mixing spaces and tabs causes an error

Output

Indented with spaces.

Verify Placement of Colons

Confirm that colons are correctly placed at the end of statements that initiate an indented block. Failure to include a colon will result in the “IndentationError.”

Python3

condition = True

if condition:
    print("Verified Colon")

Output

Verified Colon

Conclusion

In conclusion, resolving the “IndentationError: expected an indented block” is straightforward and involves carefully inspecting the indentation of your code. Ensure that proper spaces or tabs are used consistently to define code blocks within control flow statements like loops or conditional structures. Double-check for any mismatched indentation levels and correct them accordingly.