[{'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:mon_cru = np.arange(1,13); mon_all = np.transpose(np.tile(mon_cru,(1,112)))\nyr_cru  = np.arange(1901,2013); yr_all = np.transpose(np.tile(yr_cru,(12,1))); yr_all = np.reshape(yr_all,(1344,1))\nncfile_tmp = netCDF4.Dataset('/Users/bcook/Documents/GEODATA/cru321/cru_ts3.21.1901.2012.tmp.dat.nc')\nncfile_pre = netCDF4.Dataset('/Users/bcook/Documents/GEODATA/cru321/cru_ts3.21.1901.2012.pre.dat.nc')\nlon = ncfile_tmp.variables['lon'][:]\nlat = ncfile_tmp.variables['lat'][:]\ni_lat = np.where((lat>=lat1_cru) & (lat<=lat2_cru)); i_lat=i_lat[0]\ni_lon = np.where((lon>=lon1_cru) & (lon<=lon2_cru)); i_lon=i_lon[0]\ntmp_month = np.zeros((np.size(mons_ave),np.size(yr_cru),np.size(i_lat),np.size(i_lon)))\npre_month = np.zeros((np.size(mons_ave),np.size(yr_cru),np.size(i_lat),np.size(i_lon)))\nfor i in enumerate(mons_ave):\nloc_mon = np.where(mon_all==i[1]); loc_mon=loc_mon[0];\ntmp=ncfile_tmp.variables['tmp'][loc_mon,i_lat,i_lon];\npre=ncfile_pre.variables['pre'][loc_mon,i_lat,i_lon];\ntmp_month[i[0],:,:,:] = tmp\npre_month[i[0],:,:,:] = pre\nprint(i)\ntmp_seas_ave = np.nanmean(tmp_month,axis=0)\npre_seas_sum = np.nansum(pre_month,axis=0)"}, {'role': 'assistant', 'content': 'data_preprocessing'}]