Syntaxerror: can’t assign to operator

Errors and bugs are inevitable and cannot be controlled, and one of them is the Python syntaxerror: can’t assign to operator error.

Are you stuck with this error and struggling to resolve it? Just keep on reading.

In this article, we’ll delve into the solutions to fix the syntaxerror cannot assign to operator.

Apart from that, you’ll also understand what this error means and why it occurs.

What is “syntaxerror can’t assign to operator” error message?

The syntaxerror: can’t assign to operator occurs when you are trying to evaluate a mathematical statement on the left side or before an assignment operator.

It triggers the error because you are trying to assign a value to something that can’t be assigned a value or is not allowed.

For example:

a = 10
b = 20
a + b = c

If you try to run this code as a result, it will throw a SyntaxError indicating cannot assign to operator.

This error message indicates an attempt to assign a value to an operator that doesn’t support assignment.

In simple words, you are trying to modify a variable or assign a new value to an operator that cannot be modified.

Why does the “syntaxerror can’t assign to operator” error occurs in Python?

The major reason why the syntaxerror cannot assign to operator keeps on bothering you it is because you are trying to perform the arithmetic operation on the left side of the assignment operator.

Unfortunately, the assignment operator cannot assign a value to it.

Here are the other common reasons why does this error occur:

👎 Mistakenly assigning a value to an operator instead of a variable. For instance, when you mistakenly write + = instead of +=, it will result in a SyntaxError.

👎 Misuse of comparison operators can lead you to this error. For instance, if you use the comparison operators like == (equality) instead of = (assignment) can lead to this error.

It usually happens when you mistakenly write a comparison statement when you intended to assign a value.

How to fix “syntaxerror: can’t assign to operator”?

To fix the syntaxerror: can’t assign to operator error in Python, ensure that all of your variable names appear on the left-hand side of an assignment operator and make sure all of your mathematical statements are located on the right side.

For example:

Incorrect code

a = 10
b = 20
a + b = c

Corrected code

a = 10
b = 20
c = a + b ✅

2. Ensure that you are not using a comparison operator “==” instead of an assignment operator “=.”

For example:

Incorrect code

a == 10 

Corrected code

a = 10 ✅

3. Ensure you are not using a hyphen in your variable names. Hyphens are not allowed in variable names in Python and are used as subtraction operators.

For example:

Incorrect code

sample-variable = 10

Corrected code

sample_variable = 10 ✅

4. Ensure you are not trying to assign a value to a literal.

Incorrect code

10 = a

Corrected code

a = 10 ✅

5. Ensure you are not trying to assign a value to a function call.

For example:

Incorrect code

def sample_function():
return 10
sample_function() = a

Corrected code

def sample_function():
return 10
a = sample_function() ✅

Conclusion

In conclusion, the error message syntaxerror: can’t assign to operator occurs when you are trying to evaluate a mathematical statement on the left side or before an assignment operator.

To fix the syntaxerror: cannot assign to operator error in Python, ensure that all of your variable names appear on the left-hand side of an assignment operator and make sure all of your mathematical statements are located on the right side.

This error message is easy to fix and understand, by executing the solutions above, you can master this Syntaxerror with the help of this guide.

You could also check out other SyntaxError articles that may help you in the future if you encounter them.

• Uncaught syntaxerror missing after argument list
• Syntaxerror: cannot assign to function call
• Syntaxerror invalid character in identifier

We are hoping that this article helps you fix the error. Thank you for reading itsourcecoders 😊

Why assignment SyntaxError happens

Assignment SyntaxErrors usually come from confusing = (assignment) with == (comparison), or trying to assign to something that isn’t a valid target.

Common triggers

• Comparison instead of assignment in if. if x = 5: — should be ==.
• Assign to a literal. 5 = x or "str" = x — literals cannot be assignment targets.
• Assign to function call. func() = x — cannot assign to a return value.
• Assign to expression. a + b = c — expressions are not targets.
• Unbalanced multi-assign. a, b = 1 — right side must match target count.

Diagnostic pattern

# BAD — = instead of ==
if x = 5:  # SyntaxError
    ...

# GOOD — use ==
if x == 5:
    ...

# Or use walrus for assignment + test
if (x := compute()) == 5:
    ...

# BAD — assign to function call
sorted(items) = new_list  # SyntaxError

# GOOD — assign the sorted result
new_list = sorted(items)

# BAD — mismatched targets
a, b = 1  # ValueError at runtime, but static tools warn

# GOOD
a, b = 1, 2

Best practices

• Use ruff or Pyright. Catches most assignment mistakes statically.
• Prefer walrus for assign-in-condition. Clearer than nested statements.
• Use type hints. Editors flag shape mismatches during autocomplete.

Caren Bautista

Technical Writer at PIES IT Solution

Responsible for crafting clear, well-structured, and beginner-friendly content across the platform. Handles the writing, proofreading, and editorial review of tutorials, guides, and documentation to ensure every article is accurate, readable, and easy to follow.

Expertise: Technical Writing · Content Creation · Documentation · Editorial Writing · JavaScript · TypeScript · Python · Python Errors · HTTP Errors · MS Excel
 · View all posts by Caren Bautista →