pandas round – Round Numbers in Series or DataFrame

To round numbers in a column or DataFrame using pandas, the easiest way is to use the pandas round() function.

df["Column"] = df["Column"].round()

If you want to round to a specific number of decimal places, you can pass the number of decimal places to the round() function.

df["Column"] = df["Column"].round(1)

Rounding numbers in a column in pandas is easy. We can round numbers in a column to the nearest integer with the pandas round() function.

Let’s say we have the following DataFrame.

df = pd.DataFrame({'Name': ['Jim', 'Sally', 'Bob', 'Sue', 'Jill', 'Larry'],
                   'Weight': [160.20, 123.81, 209.45, 150.35, 102.43, 187.52]})

print(df)
# Output: 
    Name  Weight
0    Jim  160.20
1  Sally  123.81
2    Bob  209.45
3    Sue  150.35
4   Jill  102.43
5  Larry  187.52

To round all of the numbers to the nearest integer in the column “weight”, we can use the pandas round() function in the following way:

df["Round of Weight"] = df["Weight"].round()

print(df)
# Output: 
    Name  Weight  Round of Weight
0    Jim  160.20            160.0
1  Sally  123.81            124.0
2    Bob  209.45            209.0
3    Sue  150.35            150.0
4   Jill  102.43            102.0
5  Larry  187.52            188.0

Rounding Numbers to Multiple Decimal Places Using pandas

We can also use the pandas round() function to round by number of decimal places. If we want to round to one decimal place, we can pass 1 to the round() function.

If we have the same DataFrame from above, you can see below how the pandas round() function will work if we want to round to the nearest decimal place.

df["Round of Weight"] = df["Weight"].round(1)

print(df)
# Output: 
    Name  Weight  Round of Weight
0    Jim  160.20            160.2
1  Sally  123.81            123.8
2    Bob  209.45            209.5
3    Sue  150.35            150.4
4   Jill  102.43            102.4
5  Larry  187.52            187.5

Using the numpy round Function to Round Numbers in DataFrame

We can also use the numpy round() function to round numbers to the nearest integer in our pandas Series and DataFrames.

If we have the same DataFrame from above, we can apply the np.round function in the following way to round all of the numbers in the “Weight” column.

df["Round of Weight"] = df["Weight"].apply(np.round)

print(df)

# Output:
    Name  Weight  Round of Weight
0    Jim  160.20            160.0
1  Sally  123.81            124.0
2    Bob  209.45            209.0
3    Sue  150.35            150.0
4   Jill  102.43            102.0
5  Larry  187.52            188.0

If you are looking to round to the nearest number in regular Python, you can use the Python round() function.

If you want to round down all the numbers in a column to the nearest integer, instead of rounding to the nearest integer , you can use the numpy floor() function.

To round up all the numbers in a column to the nearest integer, instead of rounding to the nearest integer, you can use the numpy ceil() function.

Hopefully this article has been helpful for you to use the pandas round() function to round numbers in a column using pandas in python.