pandas add count of repeated elements from column
# Basic syntax: # Get counts of duplicated elements in one column: dataframe.pivot_table(index=['column_name'], aggfunc='size') # Get counts of duplicated elements across multiple columns: dataframe.pivot_table(index=['column_1', 'column_2',...], aggfunc='size') # Note, the column (column_name) doesn't need to be sorted # Note, this will return a Series object containing column_name and # a column with the number of occurrences of each value in column_name # One approach to adding the counts back to the original dataframe: counts = dataframe.pivot_table(index=['column_name'], aggfunc='size') counts = pd.DataFrame(counts) # Convert Series to DataFrame counts.index.name = 'column_name' counts.reset_index(inplace=True) # Change row names to be a column counts.columns = ['column_name', 'counts'] dataframe = dataframe.merge(counts) # Merge dataframes on common column
