How do you round up 0.5 in python?
I am facing a strange behavior of the Show
This code prints:
I expected the floating values to be always rounded up, but instead, it is rounded to the nearest even number. Why such behavior, and what is the best way to get the correct result? I tried to use the
martineau 115k25 gold badges160 silver badges284 bronze badges asked Oct 8, 2015 at 15:11
4 The Numeric Types section documents this behaviour explicitly:
Note the rounding half to even. This is also called bankers rounding; instead of always rounding up or down (compounding rounding errors), by rounding to the nearest even number you average out rounding errors. If you need more control over the rounding behaviour, use the For example, to round up from half:
answered Oct 8, 2015 at 15:24
Martijn Pieters♦Martijn Pieters 986k274 gold badges3878 silver badges3238 bronze badges 3 For example:
answered Oct 8, 2015 at 15:28
dhobbsdhobbs 3,1071 gold badge17 silver badges18 bronze badges You can use this:
It will round number up or down properly. answered Dec 18, 2016 at 7:20
fedor2612fedor2612 4214 silver badges6 bronze badges 2
If you want this to work properly for negative numbers use:
Note, this can mess up for large numbers or really precise numbers like answered Jul 31, 2017 at 19:51
3 The behavior you are seeing is typical IEEE 754 rounding behavior. If it has to choose between two numbers that are equally different from the input, it always picks the even one. The advantage of this behavior is that the average rounding effect is zero - equally many numbers round up and down. If you round the half way numbers in a consistent direction the rounding will affect the expected value. The behavior you are seeing is correct if the objective is fair rounding, but that is not always what is needed. One trick to get the type of rounding you want is to add 0.5 and then take the floor. For example, adding 0.5 to 2.5 gives 3, with floor 3. answered Oct 8, 2015 at 15:24
0 Love the fedor2612 answer. I expanded it with an optional "decimals" argument for those who want to use this function to round any number of decimals (say for example if you want to round a currency $26.455 to $26.46).
Output:
answered Oct 2, 2018 at 23:47
Joe CatJoe Cat 1591 silver badge8 bronze badges 1 Why make it so complicated?
You could of course make it into a lambda which would be:
answered Jun 20, 2021 at 22:50
TeaCoastTeaCoast 1861 silver badge10 bronze badges 3 Short version: use the decimal module. It can represent numbers like 2.675 precisely, unlike Python floats where 2.675 is really 2.67499999999999982236431605997495353221893310546875 (exactly). And you can specify the rounding you desire: ROUND_CEILING, ROUND_DOWN, ROUND_FLOOR, ROUND_HALF_DOWN, ROUND_HALF_EVEN, ROUND_HALF_UP, ROUND_UP, and ROUND_05UP are all options. answered Oct 8, 2015 at 15:20
rmunnrmunn 33.1k9 gold badges71 silver badges103 bronze badges 0 Rounding to the nearest even number has become common practice in numerical disciplines. "Rounding up" produces a slight bias towards larger results. So, from the perspective of the scientific establishment, answered Oct 8, 2015 at 15:19
MRocklinMRocklin 53.1k21 gold badges146 silver badges220 bronze badges 1 In
the question this is basically an issue when dividing a positive integer by 2. The easisest way is However we cannot apply this to series, therefore what we then can do for example for a pandas dataframe, and without going into loops, is:
answered Jul 11, 2019 at 9:40
A small addition as the rounding half up with some of the solutions might not work as expected in some cases. Using the function from above for instance:
Where I was expecting
answered Jun 15, 2021 at 7:50
dodgedodge 311 silver badge4 bronze badges Here is another solution. It will work as normal rounding in excel.
answered Nov 15, 2018 at 23:18
discoverdiscover 3591 gold badge4 silver badges14 bronze badges 1 The following
solution achieved "school fashion rounding" without using the
e.g.
answered Dec 20, 2018 at 15:51
So just to make sure there is a crystal clear working example here, I wrote a small convenience function
And an appropriate set of test cases
answered Dec 19, 2020 at 15:43
You can use:
answered Oct 8, 2015 at 15:29
cdontscdonts 8,8983 gold badges42 silver badges70 bronze badges A classical mathematical rounding without any libraries
answered Dec 16, 2018 at 14:12 Knowing that Goal: Provide lower and higher round number depending on
Some testing: yw answered Nov 9, 2019 at 18:54
gies0rgies0r 4,0451 gold badge35 silver badges43 bronze badges
answered Mar 26, 2020 at 11:06
LetzerWilleLetzerWille 5,2214 gold badges22 silver badges26 bronze badges You can try this
it will work since answered Jul 5, 2019 at 7:32
seVenVo1dseVenVo1d 3686 silver badges15 bronze badges 1 Can 0.5 be rounded?0.5 rounded off to the nearest whole number is 1. Since, the value after decimal is equal to 5, then the number is rounded up to the next whole number. Hence, the whole number of 0.5 will be 1.
How do I get Python to round up?To implement the “rounding up” strategy in Python, we'll use the ceil() function from the math module. The ceil() function gets its name from the term “ceiling,” which is used in mathematics to describe the nearest integer that is greater than or equal to a given number.
How do you round decimals in Python?To round to the nearest whole number in Python, you can use the round() method. You should not specify a number of decimal places to which your number should be rounded. Our Python code returns: 24. The round() function is usually used with floating-point numbers, which include decimal places.
Does Python round down or up?In this article, we talked about three built-in functionalities in Python that let us round numbers. The round() function rounds a number to the nearest whole number. The math. ceil() method rounds a number up to the nearest whole number while the math.
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