Variables or expressions inside {} are evaluated at runtime.
You can use any valid Python expression inside the braces.
Faster and more readable than other methods.
Examples:
name = "Alice"
age = 30
height = 1.68
print(f"My name is {name}, I am {age} years old and {height:.2f} meters tall.")
Output:
My name is Alice, I am 30 years old and 1.68 meters tall.
Advanced formatting with f-strings:
pi = 3.1415926535
print(f"Pi to 3 decimal places: {pi:.3f}")
print(f"Binary of 10: {10:b}")
# Padded Output with zeros (5 digits): 00042
print(f"Padded number: {42:05d}")
🔷 2. str.format() Method – Python 2.7+ / 3.x
Syntax:
"string with placeholders {}".format(values)
Placeholder
Description
{}
Automatic
{0}, {1}
Positional
{name}
Keyword
Examples
# Positional arguments
print("Hello {}, you are {} years old.".format("Alice", 30))
# Indexed placeholders
print("Hello {0}, you are {1} years old. {0}, have a great day!".format("Alice", 30))
# Named arguments
print("Name: {name}, Age: {age}".format(name="Bob", age=25))
# Mixing types
pi = 3.14159
print("Pi is approximately {:.2f}".format(pi)) # Output: Pi is approximately 3.14
Padding and alignment:
# Width and alignment
print("{:<10}".format("left")) # 'left '
print("{:^10}".format("center")) # ' center '
print("{:>10}".format("right")) # ' right'
