[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify code snippets into one of the following categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']."}, {'role': 'user', 'content': "Identify the single most appropriate category to which the provided code belongs. Provide your response as a single category label without any additional information, commentary, or personal opinions.\\nPython Code:df['address'] = df['display_address'].astype('category').cat.codes\ndf['street_address'] = df['street_address'].astype('category').cat.codes\ndf['building_id'] = df['building_id'].astype('category').cat.codes\ndf['manager_id'] = df['manager_id'].astype('category').cat.codes\ndf['num_features'] = df['features'].apply(len)\ndf['created'] = pd.to_datetime(df['created'])\ndf['created_year'] = df['created'].dt.year.astype('category').cat.codes\ndf['created_month'] = df['created'].dt.month.astype('category').cat.codes\ndf['len_description'] = df['description'].apply(lambda x: len(x.split(' ')))\ndf['num_pics'] = df['photos'].apply(len)"}, {'role': 'assistant', 'content': 'data_preprocessing'}]