[{'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:data["date"] = data.datetime.apply(lambda x : x.split()[0])\ndata["hour"] = data.datetime.apply(lambda x : x.split()[1].split(":")[0]).astype("int")\ndata["year"] = data.datetime.apply(lambda x : x.split()[0].split("-")[0])\ndata["weekday"] = data.date.apply(lambda dateString : datetime.strptime(dateString,"%Y-%m-%d").weekday())\ndata["month"] = data.date.apply(lambda dateString : datetime.strptime(dateString,"%Y-%m-%d").month)'}, {'role': 'assistant', 'content': 'data_preprocessing'}]