Catching SyntaxError Exceptions in Python
Syntax errors in Python can be caught using try-except blocks. However, SyntaxError exceptions are typically not caught at runtime because they indicate invalid Python code that needs to be fixed during development.
Example:
try:
exec("print('Hello, world!'")
except SyntaxError as e:
print("Syntax error occurred:", e)
Fixing Invalid SyntaxError in Python
To fix SyntaxError in Python, carefully review the code for any missing parentheses, brackets, colons, or other syntax errors, and correct them accordingly.
Example:
Python
print("Hello, world!")
You can also try this code with Online Python Compiler
Output
Hello, world!
Reasons for Syntax Errors in Python
Syntax errors in Python occur due to incorrect use of Python syntax rules, such as missing or mismatched brackets, parentheses, colons, or quotes, or incorrect indentation levels.
Now we will be discussing common reasons for syntax errors in python.
Missing of brackets
print("Hello world."
Output
ERROR!
Traceback (most recent call last):
File "<main.py>", line 1
print("Hello world."
^
SyntaxError: '(' was never closed
Here we can see that the output screen clearly shows that a bracket is missing at the end.
Inconsistent indentation
Python
def one():
return 1
def two():
return 2
print("Choose operation.")
print("1.Return 1")
print("2.Return 2")
while True:
choice = input("Enter 1 or 2: ")
if choice in ('1', '2'):
#incorrect indentation
if choice == '1':
print("1")
elif choice == '2':
print("2")
next = input("Print again? (yes/no): ")
if next == "no":
break
else:
print("Invalid Input")
You can also try this code with Online Python Compiler
Output
ERROR!
Traceback (most recent call last):
File "<main.py>", line 15
if choice == '1':
^^
IndentationError: expected an indented block after 'if' statement on line 13
Indentation plays an important role in python code. Wrong indentation results in an error in Python. Here, the output screen indicates where indentation is wrongly used.
Missing of Colon
Python
#Missing of colon
def one()
return 1
def two():
return 2
print("Choose operation.")
print("1.Return 1")
print("2.Return 2")
while True:
choice = input("Enter 1 or 2: ")
if choice in ('1', '2'):
if choice == '1':
print("1")
elif choice == '2':
print("2")
next = input("Print again? (yes/no): ")
if next == "no":
break
else:
print("Invalid Input")
You can also try this code with Online Python Compiler
Output
ERROR!
Traceback (most recent call last):
File "<main.py>", line 2
def one()
^
SyntaxError: expected ':'
After any function or compound statement such as if, else, while, for, the colon is required after the condition.
Also see, Convert String to List Python
Using keywords as a variable name
Python
def one():
return 1
def two():
return 2
print("Choose operation.")
print("1.Return 1")
print("2.Return 2")
while True:
#keyword used as a variable name
def = input("Enter 1 or 2: ")
if def in ('1', '2'):
if def == '1':
print("1")
elif def == '2':
print("2")
next = input("Print again? (yes/no): ")
if next == "no":
break
else:
print("Invalid Input")
You can also try this code with Online Python Compiler
Output
ERROR!
Traceback (most recent call last):
File "<main.py>", line 13
def = input("Enter 1 or 2: ")
^
SyntaxError: invalid syntax
def is a keyword in Python. So, using it results in invalid syntax.
Not Understanding the difference between “=” and “==”
Python
def one():
return 1
def two():
return 2
print("Choose operation.")
print("1.Return 1")
print("2.Return 2")
while True:
#using == instead of =
def == input("Enter 1 or 2: ")
if def in ('1', '2'):
if def == '1':
print("1")
elif def == '2':
print("2")
next = input("Print again? (yes/no): ")
if next == "no":
break
else:
print("Invalid Input")
You can also try this code with Online Python Compiler
Output
ERROR!
Traceback (most recent call last):
File "<main.py>", line 13
def == input("Enter 1 or 2: ")
^^
SyntaxError: invalid syntax
“=” is used for assigning something, and “==” is used for checking the equality condition.
Non-Matching Quotation marks
Python
print("Hello World')
You can also try this code with Online Python Compiler
Output
ERROR!
Traceback (most recent call last):
File "<main.py>", line 1
print("Hello World')
^
SyntaxError: unterminated string literal (detected at line 1)
If the string contained in quotation marks starts with double quotes, it should end with double quotes.
In Python code, indentation plays the most important part. Make sure that your code is well indented. You can try it on online python compiler.
It's time to discuss some FAQs related to the Invalid Syntax in Python.
Frequently Asked Questions
What do you mean by Syntax in Python?
Syntax generally refers to a set of rules predefined to be followed to come up with the correct output.
How can one fix the invalid syntax in Python?
Read the error message properly. Tracebacks are good enough to find the reason for mistakes in your code.
What are the different types of programming errors?
Basically, there are three different types of programming errors: Syntax error, Runtime error and logical errors.
Why am I getting invalid syntax in Python for no reason?
Invalid syntax errors in Python typically occur due to missing or mismatched brackets, parentheses, colons, or quotes, or incorrect indentation levels in the code.
Conclusion
We have discussed the Invalid Syntax in Python, including its example and the error that would be displayed on the output screen.
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