Count Distinct Values by Group of pandas DataFrame Column in Python (Example Code)

import pandas as pd                               # Import pandas library to Python

import pandas as pd # Import pandas library to Python

my_df = pd.DataFrame({'A':[7, 7, 4, 1, 2, 8, 2],  # Construct example DataFrame in Python
                      'B':[1, 1, 1, 2, 2, 2, 3]})
print(my_df)                                      # Display example DataFrame in console
#    A  B
# 0  7  1
# 1  7  1
# 2  4  1
# 3  1  2
# 4  2  2
# 5  8  2
# 6  2  3

my_df = pd.DataFrame({'A':[7, 7, 4, 1, 2, 8, 2], # Construct example DataFrame in Python 'B':[1, 1, 1, 2, 2, 2, 3]}) print(my_df) # Display example DataFrame in console # A B # 0 7 1 # 1 7 1 # 2 4 1 # 3 1 2 # 4 2 2 # 5 8 2 # 6 2 3

print(my_df.groupby('B')['A'].nunique())          # Count unique values in column
# B
# 1    2
# 2    3
# 3    1

print(my_df.groupby('B')['A'].nunique()) # Count unique values in column # B # 1 2 # 2 3 # 3 1