Python f string escape curly: Is it possible?

This article will explain what the “python f string escape curly” means, what causes it, and how to resolve it. Rectifying any key error generated while using f-string is very easy and simple. The Python f-string allows the you to set expressions inside the string literals using curly braces { }.

Let us look and try to understand the cause of the Python f string escape curly error and how to rectify it.

What is Python f string escape curly?

In Python programming language, a formatted string literal or f-string is a smooth and accessible string that is used for different purposes such as expression evaluation, string alignment, etc.; it allows you to set expressions inside the string literals using curly braces { }—however, formatted literal strings. However, double curly braces should be used if a literal is placed inside an f-string.

This shorthand method is used to evaluate formatted string expressions. When assessing at runtime, these formatted string literals hold great significance in the Python programming language. These formatted string literals hold quality importance and can be used alongside different functions such as a dictionary, as a calling function, as escaping characters or format datetime or floats, etc.,

Here, talking about escape characters such as quotes or curly braces. These are solely used to help with the differentiation between formatted literal string values and syntaxes. To escape a single quote, we use a backslash; similarly, to escape a curly bracket, we come up with doubling the character.

How is Python f string escape curly generated?

The Python f string escape curly warning is generated when a Python interpreter comes across an open curly brace inside an f-string which is not followed by a closing curly brace } or a rational expression; due to this, the interpreter assumes that the starting open brace is the start of an f string and the interpreter eventually expects the closing curly brace to terminate the given expression.

Whenever you try to use a single curly brace in format string then while executing the code, a keyerror is generated as KeyError: ‘Message\\’; here in the illustration below, a Python statement is executed, which prints the formatted string with a place holder for an integer value taking an argument which is further passed to the format() method.

print(" \{ Welcomes to Python Programming \} {0} ".format(42))


KeyError: ' Welcomes to Python Programming \\'

How do you resolve the Python f string escape curly?

Here are two simple ways of resolving Python f string escape curly.

Use double curly brace {{ }}

Whenever there is a need for literal curly braces inside formatted string literal, double curly braces should be used to escape and prevent the literal from being treated as expression placeholders.

df = " {{ Welcomes to Python Programming }} {0} "

#Returns { Welcomes to Python Programming } 42 

Assigning an integer value

The variable is assigned to the formatted string literal regardless of the value type like integers or strings or any other data type, regardless of the point that escaping literal curly braces inside formatted string literal is obligatory.

num = 42 
print(f" {{Welcomes to Python Programming}} {num} ")

# Returns {Welcomes to Python Programming} 42 


Can f-strings be used with previous Python versions?

No, you cannot use f-strings with the previous Python versions because f-strings were introduced in Python 3.6, so they will not be available in older versions of Python. If you want to use f-strings in older versions of Python, then you need to use an alternative string formatting method.

Are f-strings suitable for formatting complicated expressions?

Yes, f-strings are suitable for formatting complicated expressions so that you can enclose the expression within curly braces {}. However, for any reason, if expression becomes too complicated, alternatives like concatenation or other string formatting methods can be used to maintain the readability and maintainability of the code.

Is it possible to remove curly braces in f-strings using triple curly braces {{{?

No, it is impossible to remove curly braces in f-strings using triple curly braces {{{ this is because using three curly braces is not a valid way to solve the persisting error in the f-strings. Not triple but double curly braces {{ should be used to escape the literal curly braces.


To conclude, python f string escape curly is a common error users and developers face when working with f-strings. This error happens inside an f-string when an opening curly brace is present without any follow-up by a close brace or a valid expression. This error can easily be solved using the different methods mentioned above. By understanding and following the best techniques mentioned in this blog, you can abstain from the occurrence of Python f string escape curly errors.


  1. f-strings
  2. KeyError

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