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The round() Function in Python

Python supports object-oriented programming and has concise, readable, and easy-to-learn syntax. It is no wonder that it is one of the most popular programming languages. An integral part of Python are its built-in functions. 

We've written a series of articles to help you learn and brush up on the most useful Python functions. In this article, we’ll learn about the round() function in Python and how to use it. 

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In this article, we’ll cover:

  • What Is the round() Function in Python and What Does It Do?
  • The round() Function in Python: Syntax
  • The round() Function in Python: Example
  • FAQs on the round() Function in Python

What Is the round() Function in Python and What Does It Do?

The round function in Python rounds a number to a specific decimal place and returns a floating-point number rounded as per our specifications. It takes the following arguments:

  1. Any number 
  2. The number of decimal places (optional)

The number of decimal places is set to zero by default. So the round() function returns the nearest integer to the number passed if the number is the only argument passed.

The round() Function in Python: Syntax


round(number, numberOfDigitsPostDecimal)

Here:

  • number refers to the number to be rounded off.
  • numberOfDigitsPostDecimal refers to the number of digits after the decimal number will be rounded off to. If you don’t provide this argument, you’ll get an integer as the result of round() applied on any float type number.

The round() Function in Python: Example 

Here, we take a look at how you can use the Python function round() next time you need it:

Code


# Rounding off integers using round()
print("Round integer 33: ")
print(round(33))

# Rounding off floating point, to show that at 0.5, it rounds to the closest even number
print("Round odd and even, positive float 33.5 and 34.5: ")
print(round(33.5))
print(round(34.5))
print("Round odd and even, negative float -33.5 and -34.5: ")
print(round(-33.5))
print(round(-34.5))

# Rounding off floating point, case of less than, equal to, and more that 0.5 being rounded off
print("Round positive float 0.4, 0.5, 0.6: ")
print(round(0.4))
print(round(0.5))
print(round(0.6))


# Rounding off floating point, case of negative numbers, less than, equal to, and more that -0.5 being rounded off
print("Round negative float -0.4, -0.5, -0.6: ")
print(round(-0.4))
print(round(-0.5))
print(round(-0.6))

# Rounding off floating point <0.5, upto various places of decimal
print("Round 0.4 upto 0,1, and 2 places of decimal: ")
print(round(0.4,0))
print(round(0.4,1))
print(round(0.4,2))

# Rounding off floating point =0.5, upto various places of decimal
print("Round 0.5 upto 0,1, and 2 places of decimal: ")
print(round(0.5,0))
print(round(0.5,1))
print(round(0.5,2))

# Rounding off floating point >0.5, upto various places of decimal
print("Round 0.6 upto 0,1, and 2 places of decimal: ")
print(round(0.6,0))
print(round(0.6,1))
print(round(0.6,2))





Output


Round integer 33: 
33
Round odd and even, positive float 33.5 and 34.5: 
34
34
Round odd and even, negative float -33.5 and -34.5: 
-34
-34
Round positive float 0.4, 0.5, 0.6: 
0
0
1
Round negative float -0.4, -0.5, -0.6: 
0
0
-1
Round 0.4 upto 0, 1, and 2 places of decimal: 
0.0
0.4
0.4
Round 0.5 upto 0, 1, and 2 places of decimal: 
0.0
0.5
0.5
Round 0.6 upto 0, 1, and 2 places of decimal: 
1.0
0.6
0.6


Note that in the case of 0.5, the round() function rounds the number off to the nearest even number.

Found this article helpful? You can learn about more Python functions in our learn folder. 

FAQs on the round() Function in Python

Q1. What does round() in Python return?

The round function in Python takes any number as an argument and returns a floating-point number rounded as per our optionally provided specifications. If no specifications are provided, it rounds to zero decimal places, giving us the nearest integer.

Q2. How do you round a float in Python 3?

You round off a float number to your desired decimal place using the built-in function round() in Python.

Q3. How do you round a number num to three decimal places in Python?

The syntax for that would look like this: round(num, 3)

Q4. In Python, the round() function rounds up or down?

The round() function can round the values up and down both depending on the situation. For <0.5, it rounds down, and for >0.5, it rounds up. For =0.5, the round() function rounds the number off to the nearest even number. So, 0.5 is rounded to zero, and so is -0.5; 33.5 and 34.5 are both rounded off to 34; -33.5 -34.5 are both rounded off to -34, and so on.

Q5. By default, round() in Python rounds to how many decimal places?

By default, if not mentioned, the round() method rounds the given number to zero decimal places.

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