[{'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:test["year"]=0\nfor i in range(len(test["Open Date"])):\n       a=test["Open Date"][i].split("/")\n       test["year"][i]=a[2]\n\ntest["month"]=0\nfor i in range(len(test["Open Date"])):\n       a=test["Open Date"][i].split("/")\n       test["month"][i]=a[0]\n    \ntest["day_No"]=0\nfor i in range(len(test["Open Date"])):\n       a=test["Open Date"][i].split("/")\n       test["day_No"][i]=a[0]\n'}, {'role': 'assistant', 'content': 'data_preprocessing'}]