[{'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:from sklearn.preprocessing import LabelEncoder\n\n# Make copy to avoid changing original data \nlabel_X_train = data_train.copy()\nlabel_X_test = data_test.copy()\n\n# Apply label encoder to each column with categorical data\nlabel_encoder = LabelEncoder()\nfor col in object_cols:\n    label_encoder.fit(pd.concat([data_train[col], data_test[col]], axis=0, sort=False))\n    label_X_train[col] = label_encoder.transform(data_train[col])\n    label_X_test[col] = label_encoder.transform(data_test[col])'}, {'role': 'assistant', 'content': "['data_preprocessing']"}]