How to use f-strings for formatting in Python
Sep 23, 2025 am 03:08 AMF-strings provide a concise way to embed expressions in strings, introduced in Python 3.6, using f"{}" syntax with variables, expressions, function calls, and formatting like {pi:.2f} for precision or {now:%Y-%m-%d} for dates, enhancing readability and performance.
F-strings, short for formatted string literals, are a clean and efficient way to embed expressions inside string literals in Python. They were introduced in Python 3.6 and are now the preferred method for string formatting due to their readability and performance.
Syntax of f-strings
To use an f-string, prefix a string with the letter f or F and include variables or expressions inside curly braces {}.
Example:
name = "Alice"age = 30
print(f"My name is {name} and I am {age} years old.")
Output:
My name is Alice and I am 30 years old.Embedding expressions
You can include not just variables, but any valid Python expression inside the curly braces.
Examples:
x = 10y = 20
print(f"The sum of {x} and {y} is {x y}.")
Output:
The sum of 10 and 20 is 30.You can also call functions or access object properties:
print(f"Uppercase: {name.upper()}")print(f"Length: {len(name)}")
Formatting numbers and dates
F-strings support format specifiers after a colon : inside the braces to control number precision, alignment, padding, and more.
Examples:
pi = 3.14159print(f"Pi rounded to two decimal places: {pi:.2f}")
Output:
Pi rounded to two decimal places: 3.14For dates:
from datetime import datetimenow = datetime.now()
print(f"Today's date: {now:%Y-%m-%d %H:%M:%S}")
Using backslashes and quotes
You cannot use backslashes inside f-string expressions. Instead, assign the value to a variable first.
For quotes, make sure to use different types inside and outside the expression:
print(f"He said \"Hello\" to {name}")Or use single and double quotes appropriately.
Basically, f-strings make string formatting simple and readable. Just remember to wrap expressions in braces and use format specifiers when needed. They’re fast and easy once you get used to the syntax.
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