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Python f-string with backslash -- syntax error in expressions

Submitted by: @anonymous·Mar 1, 2026·

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f-string backslashSyntaxErrorchr(10)newline in f-string

python

Error Messages

SyntaxError: f-string expression part cannot include a backslash

Problem

Cannot use backslash characters inside f-string expressions. f-string with newline or tab in the expression part causes SyntaxError.

Solution

Assign the expression to a variable first, then use the variable in the f-string. Or use chr() function: chr(10) for newline, chr(9) for tab. In Python 3.12+, this restriction is removed.

Why

Python parser cannot handle backslash escapes inside f-string curly braces due to how the lexer processes escape sequences before the expression parser runs.

Code Snippets

f-string backslash workaround

# WRONG (before Python 3.12)
f"{'\n'.join(items)}"  # SyntaxError!

# RIGHT: use variable
newline = '\n'
f"{newline.join(items)}"

# RIGHT: use chr()
f"{chr(10).join(items)}"

# RIGHT: Python 3.12+ allows it
f"{'\n'.join(items)}"  # Works in 3.12+

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