Python nunique - Python Pandas Series nunique() Function

Pandas Series nunique() Function:

Python nunique: The nunique() method of the Pandas module returns the number of unique items in a given Series.

Syntax:

Series.nunique(dropna=True)

Parameters

dropna: This is optional. To include NaN in the counts, set False. True is the default value.

Return Value:

The number of unique elements present in the given Series is returned by the nunique() function of the Pandas Series

Python Pandas Series nunique() Function

Example1

Approach:

Import pandas module using the import keyword.
Pass some random list as an argument to the Series() function of the pandas module to create a series.
Store it in a variable.
Print the above-given series.
Apply nunique() function on the given series to get the count of number of unique elements present in the given series and print the result.
The Exit of the Program.

Below is the implementation:

# Import pandas module using the import keyword.
import pandas as pd
# Pass some random list as an argument to the Series() function
# of the pandas module to create a series.
# Store it in a variable.
gvn_series = pd.Series([3, 4, 1, 5, 4, 1, 3])
# Print the above given series
print("The given series is:")
print(gvn_series)
print()
# Apply nunique() function on the given series to get the 
# count of number of unique elements present in the given series
# and print the result.
print("The count of number of unique elements in the given series:")
print(gvn_series.nunique())

Output:

The given series is:
0    3
1    4
2    1
3    5
4    4
5    1
6    3
dtype: int64

The count of number of unique elements in the given series:
4

Example2

Pandas nunique: Here, the nunique() function is used on a specified series/columns of a DataFrame.

Approach:

Import pandas module using the import keyword.
Pass some random key-value pair(dictionary), index list as arguments to the DataFrame() function of the pandas module to create a dataframe.
Store it in a variable.
Print the given dataframe.
Get the count of the number of unique elements present in the student_marks column of the dataframe using the nunique() function and print the result.
The Exit of the Program.

Below is the implementation:

# Import pandas module using the import keyword.
import pandas as pd
# Pass some random key-value pair(dictionary), index list as arguments to the 
# DataFrame() function of the pandas module to create a dataframe
# Store it in a variable.
data_frme = pd.DataFrame({
  "student_rollno": [1, 2, 3, 4, 5, 6],
  "student_marks": [90, 35, 25, 90, 25, 90]},
  index= ["virat", "nick" , "jessy", "sindhu", "john", "mary"]
)
# Print the given dataframe
print("The given Dataframe:")
print(data_frme)
print()
# Get the count of number of unique elements present in the student_marks 
# column of the dataframe using the nunique() function and print the result
print("Number of unique elements present in student_marks column of the dataframe:")
print(data_frme['student_marks'].nunique())

Output:

The given Dataframe:
        student_rollno  student_marks
virat                1             90
nick                 2             35
jessy                3             25
sindhu               4             90
john                 5             25
mary                 6             90

Number of unique elements present in student_marks column of the dataframe:
3

Python nunique – Python Pandas Series nunique() Function

Python Pandas Series nunique() Function

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