How to limit floats to two decimal points in Python? One solution to limit floats to two decimal points is to use the `round()` function, which rounds a number to a specified number of decimal points.

However, there are several other methods for limiting floats to two decimal points in Python, including string formatting, f-strings, and the `Decimal` module. In this article, we will explain all these methods with examples.

## 1. Quick Examples of Limiting Floats to Two Decimal Points

These are examples of different methods of limiting floats to two decimal points in Python. These examples should give you a high-level overview of each method and its syntax.

``````
# Quick examples of limiting floats to two decimal points

# Example 1: Using the round() function
rounded_num = round(num, 2)
print(rounded_num)

# Example 2: Using string formatting
rounded_num = "{:.2f}".format(num)
print(rounded_num)

# Example 3: Using f-strings
rounded_num = f"{num:.2f}"
print(rounded_num)

# Example 4: Using the format() function
rounded_num = format(num, ".2f")
print(rounded_num)
``````

## 2. round() – Round up Floats to Two Decimal Points

To limit a float to two decimal points use the Python `round()` function, you simply need to pass the float as the first argument and the value `2` as the second argument.

The `round()` function is used to round a number to a specified number of decimal points. By default, `round()` rounds to the nearest integer, but you can specify the number of decimal points by passing a second argument to the function.

See the following Example:

``````
# Using round()
num = 3.141592653589793
rounded_num = round(num, 2)
print("Float rounded up to two decimal points:", rounded_num)
``````

Yields below output.

The `round()` function uses the “Round Half to Even” rule, also known as “banker’s rounding”. If you round `2.5` to one decimal point using `round(2.5, 1)`, the result will be `2.4`, not `2.5`.

This is because `2.5` is exactly halfway between `2.4` and `2.6`, so `round()` rounds down to the nearest even number (`2`), rather than up to the nearest odd number (`3`).

Look at the following example to understand the “Round Half to Even”:

``````
# round() examples
num1 = 2.5
num2 = 3.5
rounded_num1 = round(num1, 0)
rounded_num2 = round(num2, 0)

print(rounded_num1)
# output: 2.0

print(rounded_num2)
# output: 4.0
``````
• `num1` is exactly halfway between `2` and `3`, so `round()` rounds down to the nearest even number (`2`).
• Similarly, `num2` is exactly halfway between `3` and `4`, so `round()` rounds up to the nearest even number (`4`).

## 3. String Formatting to Limit Float to Specific Points

Formatted String is an important feature of Python. We can use it to control the way numbers are displayed by specifying formatting options.

To limit a float to two decimal points using Python string formatting, you can use the format string `{:.2f}`, where the `2` specifies the number of decimal points to display and the `f` indicates that the argument should be formatted as a float.

``````
# Using string formatting
formatted_num = "{:.2f}".format(num)
print(formatted_num)
``````

With String formatting, we can easily concatenate the number with a larger string. See the following example:

``````
# String formatting examples
dollars = 1234567.89
formatted_dollars = "\${:,.2f}".format(dollars)
print(formatted_dollars)

# Output:
# \$1,234,567.89
``````

String formatting can also be achieved using the f-string syntax. To limit a float to two decimal points using f-strings, you can include the expression inside braces (`{}`) and use the format string `:.2f`.

``````
# Using f-string
formatted_num = f"{num:.2f}"
print(formatted_num)

# Output: 3.14
``````

## 4. Use Decimal Module

Python’s built-in `decimal` module provides support for exact decimal arithmetic, which can be useful when working with financial or other numerical data that requires precise calculations.

To limit a float to two decimal points using the `decimal` module, you can create a `Decimal` object from the float and then use the `quantize()` method to round the value to the desired number of decimal places.

``````
# Import decimal module
from decimal import Decimal

num = 3.141592653589793
decimal_num = Decimal(str(num))
rounded_num = decimal_num.quantize(Decimal('.01'))
print(rounded_num)

# Output: 3.14
``````

You can specify different rounding modes (e.g., rounding up or down) or adjust the precision of the calculation to more than two decimal points if necessary.

``````
from decimal import Decimal, ROUND_HALF_UP

dollars = 1234567.895
decimal_dollars = Decimal(str(dollars))
rounded_dollars = decimal_dollars.quantize(Decimal('.01'), rounding=ROUND_HALF_UP)
formatted_dollars = "\${:,.2f}".format(rounded_dollars)
print(formatted_dollars)

# Output: \$1,234,567.90
``````

## Frequently Asked Questions on Python Limit Floats to Two Decimal Points

How can I round a float to two decimal points in Python?

You can use the `round()` function or format the float as a string using the `format()` method or f-strings.

Can I achieve precise decimal rounding using the decimal module?

You can achieve precise decimal rounding using the `decimal` module in Python. The `decimal` module provides the `Decimal` data type, which allows for more control over precision and rounding compared to the built-in `float` type.

What’s the difference between rounding and formatting for two decimal points?

Rounding with `round()` alters the numerical value, while formatting as a string preserves the original value but displays it with the specified precision. Choose based on your specific use case.

Are there performance considerations when using the decimal module?

The `decimal` module can be slower than working with native floats due to increased precision and complexity. Use it when precise decimal arithmetic is necessary, such as in financial applications.

How do I choose between rounding methods?

The choice of rounding method (rounding down, up, or to the nearest) depends on your specific requirements. Use `round()` or `math.ceil()` for rounding, and the `decimal` module for precise control over rounding methods.

## Summary and Conclusion

We have explained multiple ways to limit floats to two decimal points in Python. You have learned the `round()` function, string formatting, f-strings, the `Decimal` module. I hope this article was helpful. Leave your queries in the comment section.

Happy Coding!!