Python: How to round to 2 (or more) decimals?

How to round to 2 decimals?

Use the built-in round() function in Python to round to 2 decimal places. The round() in function accepts two arguments. The first one the value to be rounded and the second one to specify the number of decimals to round. # round to 2 decimal places myFloat = 2.4444 rounded = round(myFloat, 2) print(rounded) As expected the round() function returns a float with 2 decimal places. In this case 2.44. 2.44

round to 3 or more decimal places

To round to 3 or more decimal places, adjust the second argument of the round function. # round to 3 or more decimal places myFloat = 2.444444444444 rounded_3_decimals = round(myFloat, 3) rounded_4_decimals = round(myFloat, 4) rounded_5_decimals = round(myFloat, 5) print('rounded to 3 decimals', str(rounded_3_decimals)) print('rounded to 4 decimals', str(rounded_4_decimals)) print('rounded to 5 decimals', str(rounded_5_decimals)) The float value is rounded to the number of digits defined in the second argument of the round() function. rounded to 3 decimals 2.444 rounded to 4 decimals 2.4444 rounded to 5 decimals 2.44444

trailing zeros are truncated

The round() function might return some surprising results. For example, trailing zeros are truncated. # round to 2 decimal places myFloat = 2.99999 rounded = round(myFloat, 2) print(rounded) The round() function returns 3.0 and truncates the second decimal place even though we specified it in the second argument. 3.0


Another surprising behavior of the round() function can be seen by rounding 2.675 to 2 decimals. # round to 2 decimal places myFloat = 2.675 rounded = round(myFloat, 2) print(rounded) Instead of the expected 2.68 the round() function returns 2.67. 2.67 This is not a bug, rather a limitation of the float type. Since most decimal fractions cannot be represented exactly as binary fractions. It is important to be aware of the limitations.

other rounding operations in Python

Python offers a variety of other rounding operations: To round up use math.ceil() or numpy.ceil() methods. To round down use the int() function or the math.floor() method. To round to nearest integer use the round() function or numpy.round(). To round to 5 (or any other number) use a custom function.



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