[{'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:cat_cols = df.select_dtypes(exclude=['number']).columns.values\n\ndrop_cols = []\nkeep_cols = []\nfor col in cat_cols:\n    if df[col].value_counts().count() > 20000 : \n        print('column {} has {} categories > drop'.format(col,df[col].value_counts().count()))\n        drop_cols.append(col)\n    else : \n        print('column {} has {} categories > keep'.format(col,df[col].value_counts().count()))\n        keep_cols.append(col)"}, {'role': 'assistant', 'content': 'data_preprocessing'}]