Remove NaN From Pandas Series

In pandas, you can use the Series.dropna() function to remove NaN (Not a Number) values from a Series. It returns new series with the same values as the original but without any NaN values. In this article, I will explain how to remove NaN from Series in Pandas by using dropna() and other methods with examples.

Key Points –

Use Pandas' built-in methods to efficiently identify and eliminate NaN values from Series.
Use Pandas functions like isnull() or notnull() to locate NaN values.
Use the dropna() method to remove NaN values from a Pandas Series.
dropna() returns a new Series with NaN entries excluded.
Use methods like dropna() to remove NaN values from the Series.
The original Series remains unchanged unless inplace=True is specified.
Removing NaN can affect the Series index unless the index is reset.
It works only on NaN values, not on other placeholders like empty strings or zeros.

Quick Examples of Remove NaN From Series

If you are in a hurry, below are some quick examples of how to remove NaN from the pandas series.


# Quick examples of remove NaN from series

# Example 1: Use dropna() 
# To remove nan values from a pandas series
ser2 = ser.dropna()

# Example 2: Use isnull() 
# To remove nan values from a pandas series
ser2 = ser[~ser.isnull()]

Syntax of Series.dropna() Function

Following is the syntax of Series.dropna() function.


# Syntax of Series.dropna() function
Series.dropna(axis=0, inplace=False, how=None)

Parameter of dropna()

Following are the parameters of the dropna().

axis - {0 or ‘index’} by default Value 0: There is only one axis to drop values from.
inplace - boolean, default Value: False: If True, do an operation in place and return None.
how - str, this optional parameter: Not in use.

Return Value

This function returns the pandas Series without NaN values.

Create Pandas Series

Now, let’s create pandas series using a list. Note that NaN in pandas and represent by using NumPy np.nan.


import pandas as pd
import numpy as np
 
# Create the Series 
ser = pd.Series(['Java', 'Spark', np.nan, 'PySpark', np.nan,'Pandas','NumPy', np.nan,'Python'])
print("Create series:\n",ser)

Yields below output.

Use dropna() Method to Remove NaN Values From Series

Using dropna() method we can remove the NaN values from the series. Let’s use Series.dropna() method to remove NaN (missing) values from the original Series to get a new series. This method returns a new Series after removing all NAN values.


# Use dropna() 
# To remove nan values from a pandas series
ser2 = ser.dropna()
print(ser2)

Yields below output.


# Output:
0       Java
1      Spark
3    PySpark
5     Pandas
6      NumPy
8     Python
dtype: object

Use isnull() Method to Remove NaN Values From Series

We can also use Series.isnull() on the original Series to get a new Series with only boolean values and the same dimensions as the original. The boolean Series contains True if the value in the original is NaN and False otherwise for each element and use this Series on the original series to remove all NaN values.


# Use isnull() 
# To remove nan values from a pandas series
ser2 = ser[~ser.isnull()]
print(ser2)

Yields the same output as above.

Complete Example For Remove NaN From Series


import pandas as pd
import numpy as np

# Create the Series  
ser = pd.Series(['Java', 'Spark', np.nan, 'PySpark', np.nan,'Pandas','NumPy', np.nan,'Python'])
print(ser)

# Example 1: Use dropna() 
# To remove nan values from a pandas series
ser2 = ser.dropna()
print(ser2)

# Example 2: Use isnull() 
# To remove nan values from a pandas series
ser2 = ser[~ser.isnull()]
print(ser2)

FAQ on Remove NaN From Pandas Series?

You can check for NaN values in a pandas Series using the isna() or isnull() method. For example, the nan_mask will be a boolean Series where each element is True if the corresponding element in the original Series is NaN and False otherwise.

You can remove NaN values from a pandas Series using the dropna() method. For example, data.dropna() returns a new Series (data_without_nan) where NaN values have been removed. If you want to modify the original Series in place, you can use the inplace parameter

You can remove NaN values from a pandas Series in place without creating a new Series by using the dropna() method with the inplace parameter set to True.

An alternative way to remove NaN values from a pandas Series is to use boolean indexing. You can use the notna() method to create a boolean mask and then use that mask to filter out the NaN values.

You can use methods like fillna() to fill NaN values with a specific value or strategy.

Conclusion

In this article, I have explained how to remove NaN values from Series in Pandas by using Series.dropna(), and Series.isnull() functions with examples.

Happy Learning !!

References

https://pandas.pydata.org/docs/reference/api/pandas.Series.dropna.html