Let’s discuss how to get unique values from a column in Pandas DataFrame.
Create a simple dataframe with dictionary of lists, say columns name are A, B, C, D, E with duplicate elements.
Now, let’s get the unique values of a column in this dataframe.
Example #1: Get the unique values of ‘B’ column
# Import pandas package import pandas as pd # create a dictionary with five fields eachdata = { 'A':['A1', 'A2', 'A3', 'A4', 'A5'], 'B':['B1', 'B2', 'B3', 'B4', 'B4'], 'C':['C1', 'C2', 'C3', 'C3', 'C3'], 'D':['D1', 'D2', 'D2', 'D2', 'D2'], 'E':['E1', 'E1', 'E1', 'E1', 'E1'] } # Convert the dictionary into DataFrame df = pd.DataFrame(data) # Get the unique values of 'B' columndf.B.unique() |
Output:
Example #2: Get the unique values of ‘E’ column
# Import pandas package import pandas as pd # create a dictionary with five fields eachdata = { 'A':['A1', 'A2', 'A3', 'A4', 'A5'], 'B':['B1', 'B2', 'B3', 'B4', 'B4'], 'C':['C1', 'C2', 'C3', 'C3', 'C3'], 'D':['D1', 'D2', 'D2', 'D2', 'D2'], 'E':['E1', 'E1', 'E1', 'E1', 'E1'] } # Convert the dictionary into DataFrame df = pd.DataFrame(data) # Get the unique values of 'E' columndf.E.unique() |
Output:
Example #3: Get number of unique values in a column
# Import pandas package import pandas as pd # create a dictionary with five fields eachdata = { 'A':['A1', 'A2', 'A3', 'A4', 'A5'], 'B':['B1', 'B2', 'B3', 'B4', 'B4'], 'C':['C1', 'C2', 'C3', 'C3', 'C3'], 'D':['D1', 'D2', 'D2', 'D2', 'D2'], 'E':['E1', 'E1', 'E1', 'E1', 'E1'] } # Convert the dictionary into DataFrame df = pd.DataFrame(data) # Get number of unique values in column 'C'df.C.nunique(dropna = True) |
Output:
