How to Get the Length of a Series in Pandas?

How to get the length of a Pandas Series? You can use the len() function to get the length of the Pandas Series. The length of the Series refers to the number of elements it contains. It is a fundamental property indicating the size of the data structure. The length of a Pandas Series is a crucial metric for effective data analysis and exploration. In this article, I will explain how to get the length of the Pandas series using multiple ways with examples.

Key Points –

• A pandas Series’ length indicates the total number of elements it holds.
• You can obtain the length of a Series using the len() function in Python.
• The len() function returns an integer representing the count of elements in the Series.
• Accessing the length of a Series is essential for understanding the size and structure of the data, facilitating data analysis and manipulation.
• Knowing the length of a Series is fundamental for various operations, such as indexing, slicing, and merging data in pandas.

Create Pandas Series in several ways by using Python lists & dictionaries, below example create a Series from a list. To use Pandas first, you need to import using import pandas as pd.

import pandas as pd

# Creating a Series
series = pd.Series([10, 20, 30, 40, 50])
print("Original Series:\n",series)

Yields below output.

Get the Length of Pandas Series

To get the length of the Pandas Series you can use the len() function. For instance, passing a given Series into the leng() function, will return the integer which is equal to the number of elements present in the Series.

# Getting the length of the Series
series_length = len(series)
print("Length of the Series:", series_length)

In the above example, a Pandas Series named series is created with values [10, 20, 30, 40, 50]. The Series is then displayed, and its length is obtained using the len() function.

Yields below output.

Get the Length of Pandas Series with Mixed Data Types

You can also get the length of the Series with mixed data types using the len() function. Let’s create a Pandas Series with mixed data types and get its length.

import pandas as pd

# Create a Pandas Series with mixed data types
mixed_series = pd.Series([10, 'Spark', 3.14, True, 'Pandas','dog'])

# Get the length of the Series
series_length = len(mixed_series)
print("Length of mixed data type series:", series_length)

# Output:
# Length of mixed data type series: 6

In the above example, the mixed_series contains elements of different data types, including integers, strings, floats, and booleans. The Series is displayed, and its length is obtained using the len() function.

Get the Length of the Custom Index Series

You can also create a Pandas Series with a custom index and get its length using the len() function. First, create a Pandas Series using a dictionary and customize its index using the index parameter. And then pass it into the len() function, which will return the count of total elements present in the Series.

import pandas as pd

# Create a Pandas Series with custom index
Courses = {'Spark': '20000', 'PySpark': '15000', 'Java': '10000'}
custom_index_series = pd.Series(Courses, index=['Courses1', 'Courses2', 'Courses3'])

# Get the length of the Series
series_length = len(custom_index_series)
print("Length of series with custom index:", series_length)

# Output:
# Length of series with custom index: 3

In the above example, a Pandas Series named custom_index_series is created with a custom index (['Courses1', 'Courses2', 'Courses3']). The Series is displayed, and its length is obtained using the len() function.

Get the Length of the DateTime Values In Series

To get the length of DateTime values present in the Series you can use the len() function. For instance, we follow a similar process as before to create a Pandas Series with datetime values. And then use the len() function to get the length of the Series and print both the Series and its length.

import pandas as pd
from datetime import datetime

# Create a list of date strings
date_strings = ['2024-01-01', '2024-01-02', '2024-01-03', '2024-01-04', '2024-01-05']

# Convert the list of date strings to datetime objects
date_objects = [pd.to_datetime(date) for date in date_strings]

# Create a Pandas Series with datetime values
date_series = pd.Series(date_objects)
print("Series with DateTime Values:\n",date_series)

# Get the length of the Series
length_of_series = len(date_series)
print("\nLength of the Series:", length_of_series)

# Output:
# Series with DateTime Values:
#  0   2024-01-01
# 1   2024-01-02
# 2   2024-01-03
# 3   2024-01-04
# 4   2024-01-05
# dtype: datetime64[ns]

# Length of the Series: 5

In another way, You can create a Pandas Series with DateTime values and obtain its length using the len() function. In this example, we can generate the range of Datetime values using the pd.date_range() function and then create a Pandas Series from that sequence. Finally, the length of the Series is calculated using the len() function.

import pandas as pd

# Create a Series with datetime values
date_range = pd.date_range('2024-01-01', periods=5)
series = pd.Series(date_range)

# Get the length of the Series
length = len(series)
print("Length of the Series with datetime values:", length)

# Output:
# Length of the Series with datetime values: 5

Get the Length of Pandas Series with NaN Value

To create a Pandas Series with NaN (Not a Number) values and get the length. For instance, create a Series containing one of the elements is NaN value (np.nan). Then use the len() function to get the length of the Series. This function will consider the NaN value and return the length of all elements present in the Series.

import pandas as pd
import numpy as np

# Create a Pandas Series with NaN values
data = [2, 4, np.nan, 6, 8]
nan_series = pd.Series(data)
print("Series with NaN Values:\n",nan_series)

# Get the length of the Series
series_length = len(nan_series)
print("Length of series with NaN values:", series_length)

# Output:
# Series with NaN Values:
#  0    2.0
# 1    4.0
# 2    NaN
# 3    6.0
# 4    8.0
# dtype: float64
# Length of series with NaN values: 5

You can replace the data with your own values containing NaN or customize the code according to your requirements.

Series with Duplicate Values

You can create a Pandas Series with duplicate values and get the length using the len() function. For example, create a Series containing duplicate values. The resulting series will have duplicate values associated with some elements. Then use the len() function to get the length of all elements(including duplicates) of the Pandas Series.

import pandas as pd

# Create a Pandas Series with duplicate values
data = [1, 2, 2, 3, 4, 4, 5]
duplicate_series = pd.Series(data)

# Get the length of the Series
series_length = len(duplicate_series)
print("Length of series with duplicate values:", series_length)

# Output:
# Length of series with duplicate values: 7

You can replace the data with your own values containing duplicates or customize the code according to your requirements.

Frequently Asked Questions on Series Length

Conclusion

In this article, I have explained how to get the length of a Pandas Series and explored different scenarios, such as working with numeric values, mixed data types, custom indexes, datetime values, NaN values, and duplicate values. The len() function was introduced to determine the length of a Pandas Series, providing the count of elements in the Series with examples.

Happy Learning!!

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• Convert Pandas Series to DataFrame 
• How To Get Value From Pandas Series?
• Pandas Series.shift() Function 
• Pandas Iterate Over Series
• Pandas Series.isin() Function
• Convert Pandas Series to String
• How to Rename a Pandas Series
• Pandas.Series.combine() Function
• Pandas Series.max() Function
• Pandas Get Floor or Ceil of Series
• Pandas Series.quantile() Function
• Pandas Series any() Function
• Pandas Series groupby() Function with Examples 
• Pandas Series unique() Function with Examples

References

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