Learn Unique Values | Analyzing the Data

Data often gets duplicated in DataFrames. For instance, in the countries DataFrame, the 'continent' column has repeated entries. There's a method that retrieves an array of distinct values from a specific DataFrame column.


              1234567
            
import pandas as pd 

country_data = {'country' : ['Thailand', 'Philippines', 'Monaco', 'Malta', 'Sweden', 'Paraguay', 'Latvia'],
          'continent' : ['Asia', 'Asia', 'Europe', 'Europe', 'Europe', 'South America', 'Europe'],
          'capital':['Bangkok', 'Manila', 'Monaco', 'Valletta', 'Stockholm', 'Asuncion', 'Riga']}
countries = pd.DataFrame(country_data)
print(countries)

Next, apply the unique() method to the 'continent' and 'country' columns:


              12345678910
            
import pandas as pd

country_data = {'country' : ['Thailand', 'Philippines', 'Monaco', 'Malta', 'Sweden', 'Paraguay', 'Latvia'],
          'continent' : ['Asia', 'Asia', 'Europe', 'Europe', 'Europe', 'South America', 'Europe'],
          'capital':['Bangkok', 'Manila', 'Monaco', 'Valletta', 'Stockholm', 'Asuncion', 'Riga']}
countries = pd.DataFrame(country_data)
unique_countries = countries['country'].unique()
unique_continents = countries['continent'].unique()
print(unique_countries)
print(unique_continents)

Sometimes, instead of retrieving all unique values, you might just want to know how many distinct values exist in a column. In such cases, you can use the nunique() method. It returns the count of unique entries in a column — not the values themselves.


              1234567
            
import pandas as pd

country_data = {'country' : ['Thailand', 'Philippines', 'Monaco', 'Malta', 'Sweden', 'Paraguay', 'Latvia'],
          'continent' : ['Asia', 'Asia', 'Europe', 'Europe', 'Europe', 'South America', 'Europe'],
          'capital':['Bangkok', 'Manila', 'Monaco', 'Valletta', 'Stockholm', 'Asuncion', 'Riga']}
countries = pd.DataFrame(country_data)
print(countries['continent'].nunique())

Task

Swipe to start coding

You are given a DataFrame named audi_cars. Your goal is to explore its data and identify unique values using Pandas methods.

Retrieve all distinct values from the 'year' column and store them in the variable unique_years.
Retrieve all distinct values from the 'fueltype' column and store them in the variable unique_fueltype.
Determine the number of unique fuel types in the 'fueltype' column using the .nunique() method and store the result in the variable count_unique_fueltypes.

Solution

Everything was clear?

Thanks for your feedback!

Section 3. Chapter 15

single

Ask AI

Ask anything or try one of the suggested questions to begin our chat

Awesome!

Completion rate improved to 3.03

Swipe to show menu


              1234567
            
import pandas as pd 

country_data = {'country' : ['Thailand', 'Philippines', 'Monaco', 'Malta', 'Sweden', 'Paraguay', 'Latvia'],
          'continent' : ['Asia', 'Asia', 'Europe', 'Europe', 'Europe', 'South America', 'Europe'],
          'capital':['Bangkok', 'Manila', 'Monaco', 'Valletta', 'Stockholm', 'Asuncion', 'Riga']}
countries = pd.DataFrame(country_data)
print(countries)