How to Quickly Round Numbers in Python

If you are working with many numbers in Python, you probably need to do some rounding to cut off some digits that you may not need at all.

For example, let us say that you are calculating an average salary in a company and the average number that you have found is around 54,334.218

This may not be a number that can look good in a final report you want to submit to someone. You should instead round it.

Let us do it in Python:

print(round(54334.218, 2)) # 54334.22

view raw round_number.py hosted with by GitHub

As you can see, the number 2 after the comma represents the number of digits we want to keep. The thing is, we can also use negative numbers to specify the number of digits we want to keep.

If we use -1, we are doing the rounding to the nearest ten:

print(round(12346, -1)) # 12350

view raw round_-1.py hosted with by GitHub

When we need to do the rounding to the nearest hundert, we use -2:

print(round(12346, -2)) # 12300

view raw round_hundert.py hosted with by GitHub

If we want to do the rounding to the nearest thousand, we use -3:

round(12346, -3) # 12000

view raw round_thousand.py hosted with by GitHub

This may seem something quite trivial, but I also got to learn it just recently.

I hope you find this useful.