Pandas Series round() Function

In Pandas, the round() function is used to round the elements of a Series to the specified number of decimal places. It is a convenient method to adjust the precision of numerical data in a Series.

In this article, I will explain the round() function, its syntax, parameters, and usage of how to get a new Pandas Series containing the rounded values based on the specified precision without modifying the original Series.

Key Points –

• The round() function in Pandas Series adjusts the precision of numerical data within the series.
• It allows rounding values to a specified number of decimal places or the nearest integer.
• The decimals parameter specifies the number of decimal places to round to, with the default being 0 for rounding to the nearest integer.
• Rounding performs on Series containing numeric data types, like integer and float.
• It returns a new Pandas Series with rounded values the original Series remains unchanged.

Syntax of Pandas Series round() Function

Following is the syntax of the pandas series round() function.

# Syntax of Pandas Series round() 
Series.round(decimals=0, *args, **kwargs)

Parameters of the Series round() Function

Following are the parameters of the round() function.

• decimals – This is an optional parameter specifying the number of decimal places to round the values to. If not provided, it defaults to 0, rounding to the nearest integer.
• args, kwargs – Additional arguments and keyword arguments that can be passed to the underlying rounding function.

Return Value

It returns a new Series with the elements rounded to the specified number of decimal places.

Rounding a Series using round() Function

By default, the Pandas Series round() function rounds the elements of a Series to the nearest integer. If you want to round the Series elements with the specified decimal value, you can use a decimals parameter of the round() function.

First, let’s create a Pandas Series from a Python list.

import pandas as pd

# Creating a Series
data = [3.14159, 2.71828, 1.41421, 4.61803, 2.23607]
series = pd.Series(data)
print("Original Series:\n",series)

Yields below output.

Here, we used the round() method on the series object to round each value in the Series to specified decimal places. The result is assigned to a new Series named rounded_series.

# Rounding the Series to 3 decimal places
rounded_series = series.round(3)
print("Rounding three decimal places:\n",rounded_series)

In the above example, the original Series series is rounded to three decimal places using the round() function, and the result is stored in the variable rounded_series. This example yields the below output.

Rounding a Series to the Nearest Integer

To round a Pandas Series to the nearest integer, you can use the round() function without specifying any decimals. By default, if no decimals are provided, the function rounds to the nearest integer.

# Rounding the Series to the nearest integer
rounded_series = series.round()
print("Rounding nearest integer:\n",rounded_series)

# Output:
# Rounding nearest integer:
# 0    3.0
# 1    3.0
# 2    1.0
# 3    5.0
# 4    2.0
# dtype: float64

In the above example, the original Series series is rounded to the nearest integer using the round() function, and the result is stored in the variable rounded_series.

Rounding a Series to the Nearest 10

To round a Pandas Series to the nearest 10, use the round() function with a negative value for the decimals parameter, indicating the desired multiple to round to.

import pandas as pd

# Creating a Pandas Series
data = [32, 68, 94, 53, 88]
series = pd.Series(data)

# Rounding the Series to the nearest 10
rounded_series = series.round(-1)
print("Rounding nearest 10's:\n",rounded_series)

# Output:
# Rounding nearest 10's:
# 0    30
# 1    70
# 2    90
# 3    50
# 4    90
# dtype: int64

In the above example, the original Series series rounds to the nearest 10 using the round() function with decimals=-1, and the result is stored in the variable rounded_series.

Rounding Series to Specified Number of Significant Digits

Similarly, to round a Series to a specified number of significant digits, you can use the round() function with a negative value for the decimals parameter, indicating the number of significant digits.

import pandas as pd

# Creating a Pandas Series
data = [1234, 5678, 9101112]
series = pd.Series(data)

# Rounding the Series to 2 significant digits
rounded_series = series.round(-2)
print("Rounding significant digits:\n",rounded_series)

# Output:
# Rounding significant digits:
# 0       1200
# 1       5700
# 2    9101100
# dtype: int64

In this example, the original Series series rounds to 2 significant digits using the round() function with decimals=-2, and the result is stored in the variable rounded_series.

Rounding a Series to the Nearest 100

You can also round a Pandas Series to the nearest 100, to do so use the round() function with decimals=-2. This indicates rounding to the nearest multiple of 100.

import pandas as pd

# Creating a Pandas Series
data = [678, 3481, 8760, 1234, 5678]
series = pd.Series(data)

# Rounding the Series to the nearest 100
rounded_series = series.round(-2)
print("Rounding nearest:\n",rounded_series)

# Output:
# Rounding nearest:
# 0     700
# 1    3500
# 2    8800
# 3    1200
# 4    5700
# dtype: int64

In the above example, the original Series series rounds to the nearest 100 using the round() function with decimals=-2, and the result is stored in the variable rounded_series.

FAQ on Series round()

Conclusion

In this article, I have explained the Pandas Series round() function, which provides a straightforward and flexible way to adjust the precision of numerical data within a Series. and also explained how to round values to a specific number of decimal places, to the nearest integer, and to a certain multiple with examples.

Happy Learning!!

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References

• https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.round.html#pandas.DataFrame.round