[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify the code snippets into categories from the provided list of categories. List of categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']"}, {'role': 'user', 'content': 'Identify to which category the provided code belongs and assign the code snippet to at least 1 but up to 5 categories based on the probabilities, ignore if the probability of the category is negligible. Strictly provide your response as a list. Avoid providing any additional information, commentary, or personal opinions.\\nPython Code:categorical = ["display_address", "manager_id", "building_id", "street_address"]<br>for f in categorical:<br>        if train_df[f].dtype==\'object\':<br>            #print(f)<br>            lbl = preprocessing.LabelEncoder()<br>            lbl.fit(list(train_df[f].values) + list(test_df[f].values))<br>            train_df[f] = lbl.transform(list(train_df[f].values))<br>            test_df[f] = lbl.transform(list(test_df[f].values))<br>            features_to_use.append(f)<br>'}, {'role': 'assistant', 'content': "['data_preprocessing']"}]