Floating values can have many decimal places, making them difficult to read and interpret.

Formatting enables us to control the number of decimal places displayed and maintain consistency throughout our application.

Here are four ways to format floats in Python:

1. Using f-strings (Python 3.6 or above)
2. Using format()
3. Using the % operator
4. Using round()

Method 1: Using f-strings

Python 3.6 introduced f-strings (formatted string literals), which are a more readable and concise way to format strings compared to older methods, such as the % operator.

# Define a floating-point value
value = 123.45678

formatted_value = f"{value:.3f}"
print("Three decimals:", formatted_value)
# Output: Three decimals: 123.457

formatted_value = f"{value:.2f}"
print("Two decimals:", formatted_value)
# Output: Two decimals: 123.46

formatted_value = f"{value:.1f}"
print("One decimal:", formatted_value)
# Output: One decimal: 123.5

formatted_value = f"{value:.0f}"
print("No decimal:", formatted_value)
# Output: No decimal: 123

Method 2: Using format()

The str.format() method lets you format floating-point numbers to a specific number of decimal places or in a specific format.

Formatting with two decimal places

value = 123.45678

formatted_value = "{:.2f}".format(value)

print(formatted_value)
# Output: 123.46

print(type(formatted_value))
# Output: <class 'str'>

The output is a string. To convert the output to a float, use the float() function.

print(float(formatted_value))
# Output: 123.46

print(type(float(formatted_value)))
# Output: <class 'float'>

Formatting with one decimal place

value = 123.45678

formatted_value = "{:.1f}".format(value)

print(float(formatted_value))
# Output: 123.5

Method 3: Using the % Operator

The % operator formats the strings oldway. You can use it for floats, and it works similarly to the format() method.

# Define a floating-point value
value = 123.45678

# Format the value to two decimal places
formatted_value = "%.2f" % value
print(formatted_value)
# Output: 123.46

# Format the value to one decimal place
formatted_value = "%.1f" % value
print(formatted_value)
# Output: 123.5

# Format the value to no decimal places
formatted_value = "%d" % value
print(formatted_value)
# Output: 123

Method 4: Using the round()

The round() function returns a floating-point number rounded to the specified number of digits after the decimal point. It does not return a string, and if you want, you must convert it.

# Define a floating-point value
value = 123.45678

formatted_value = round(value, 3)
print("Three decimals:", formatted_value)
# Output: 123.457

formatted_value = round(value, 2)
print("Two decimals:", formatted_value)
# Output: 123.46

formatted_value = round(value, 1)
print("One decimal:", formatted_value)
# Output: 123.5

That’s all!

Krunal Lathiya

With a career spanning over eight years in the field of Computer Science, Krunal’s expertise is rooted in a solid foundation of hands-on experience, complemented by a continuous pursuit of knowledge.