[{'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:def get_word_frequency(sparse_matrix,doc,word_list):\nnum_words = sparse_matrix[doc,:].getnnz()\nword_frequency = pd.DataFrame(index=range(num_words), columns=['word','frequency'])\ncx = scipy.sparse.coo_matrix(sparse_matrix[doc,:])\nfor i,j,k in zip(cx.col,cx.data,range(num_words)):\nword_frequency['word'][k] = word_list[i]\nword_frequency['frequency'][k] = j\nword_frequency.sort_values('frequency',inplace=True,ascending=False)\nreturn word_frequency"}, {'role': 'assistant', 'content': "['data_preprocessing']"}]