Pandas Series Index() Methods

Pandas series is a One-dimensional ndarray with axis labels. The labels need not be unique but must be a hashable type. The object supports both integer- and label-based indexing and provides a host of methods for performing operations involving the index. 

Pandas Series.index attribute is used to get or set the index labels of the given Series object.

Pandas Series Index() Methods

Syntax: Series.index()

Returns : index

Pandas Series Index Example

Use Series.index attribute to set the index label for the given Series object. 

Python3

# importing pandas as pd
import pandas as pd

# Creating the Series
series = pd.Series(['New York', 'Chicago', 'Toronto', 'Lisbon'])

# Print the series
print(series)

Output:

0    New York
1     Chicago
2     Toronto
3      Lisbon
dtype: object

Now we will use Series.index attribute to set the index label for the given object. 

Python3

# Creating the row axis labels
series.index = ['City 1', 'City 2', 'City 3', 'City 4']

# Print the series
print(series)

Output : 

City 1    New York
City 2     Chicago
City 3     Toronto
City 4      Lisbon
dtype: object

As we can see in the output, the Series.index attribute has successfully set the index labels for the given Series object. 

We can also assign duplicate or nonunique indexes in pandas.

Python3

# Creating the row axis labels
series.index = ['City 1', 'City 1', 'City 3', 'City 3']

# Print the series
print(series)

Output:

City 1    New York
City 1     Chicago
City 3     Toronto
City 3      Lisbon
dtype: object

Find element’s index in pandas Series

Use Series.index attribute to get the index labels of the given Series object. 

Python3

# importing pandas as pd
import pandas as pd

Date = ['1/1/2018', '2/1/2018', '3/1/2018', '4/1/2018']
Index_name = ['Day 1', 'Day 2', 'Day 3', 'Day 4']

# Creating the Series
sr = pd.Series(data = Date,        # Series Data
              index = Index_name   # Index
              )

# Print the series
print(sr)

Output : 

Day 1    1/1/2018
Day 2    2/1/2018
Day 3    3/1/2018
Day 4    4/1/2018
dtype: object

Now we will use Series.index attribute to get the index label for the given object. 

Python3

# print the index labels
print(sr.index)

Output : 

Index(['Day 1', 'Day 2', 'Day 3', 'Day 4'], dtype='object') 

As we can see in the output, the Series.index attribute has successfully returned the index labels for the given Series object.