Using dictionary to remap values in Pandas DataFrame columns

While working with data in Pandas, we perform a vast array of operations on the data to get the data in the desired form. One of these operations could be that we want to remap the values of a specific column in the DataFrame. Let’s discuss several ways in which we can do that.

Given a Dataframe containing data about an event, remap the values of a specific column to a new value.

Code #1: We can use DataFrame.replace() function to achieve this task. Let’s see how we can do that.



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# importing pandas as pd
import pandas as pd
  
# Creating the DataFrame
df = pd.DataFrame({'Date':['10/2/2011', '11/2/2011', '12/2/2011', '13/2/2011'],
                    'Event':['Music', 'Poetry', 'Theatre', 'Comedy'],
                    'Cost':[10000, 5000, 15000, 2000]})
  
# Print the dataframe
print(df)

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Output : 




Now we will remap the values of the ‘Event’ column by their respective codes. 













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# Create a dictionary using which we 


# will remap the values 


dict = {'Music' : 'M', 'Poetry' : 'P', 'Theatre' : 'T', 'Comedy' : 'C'} 


  


# Print the dictionary 


print(dict) 


  


# Remap the values of the dataframe 


df.replace({"Event": dict}) 



















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Output : 






 


Code #2:  We can use map() function to achieve this task.











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# importing pandas as pd 


import pandas as pd 


  


# Creating the DataFrame 


df = pd.DataFrame({'Date':['10/2/2011', '11/2/2011', '12/2/2011', '13/2/2011'], 


                    'Event':['Music', 'Poetry', 'Theatre', 'Comedy'], 


                    'Cost':[10000, 5000, 15000, 2000]}) 


  


# Print the dataframe 


print(df) 



















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Output : 




Now we will remap the values of the ‘Event’ column by their respective codes. 













                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















# Create a dictionary using which we 


# will remap the values 


dict = {'Music' : 'M', 'Poetry' : 'P', 'Theatre' : 'T', 'Comedy' : 'C'} 


  


# Print the dictionary 


print(dict) 


  


# Remap the values of the dataframe 


df['Event']= df['Event'].map(dict) 


  


# Print the DataFrame after modification 


print(df) 



















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Output : 







          
          
          
          

            

    

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