用python优化它：这段代码什么意思：n=4 df = pd.DataFrame({'group': list('aabbabbbababaababbba'), 'value': [1,2,np.nan,2,4,np.nan,9,2,np.nan,3,7,6,8,np.nan,6,np.nan,np.nan,0,6,5]}) ndfa=df[df["group"] == "a"] ndfb=df[df["group"] == "b"] movingaverage1=[] movingaverage2=[] len1=len(ndfa["value"]) len2=len(ndfb["value"]) for i in range(1,len1+1): if i<=n: if True in np.array(np.isnan((ndfa[:1])["value"])): movingaverage1.append(0) else: sub_ndfa=ndfa[:i] sub_ndfa_withoutNaN=sub_ndfa[pd.notnull((sub_ndfa["value"]))]["value"] movingaverage1.append((sub_ndfa_withoutNaN.copy()).mean()) else: sub_ndfa=ndfa[i-n:i] sub_ndfa_withoutNaN=sub_ndfa[pd.notnull((sub_ndfa["value"]))]["value"] movingaverage1.append((sub_ndfa_withoutNaN.copy()).mean()) for i in range(1,len2+1): if i<=n: if True in np.array(np.isnan((ndfb[:1])["value"])): movingaverage2.append("0") else: sub_ndfb=ndfb[:i] sub_ndfb_withoutNaN=sub_ndfb[pd.notnull((sub_ndfb["value"]))]["value"] movingaverage2.append((sub_ndfb_withoutNaN.copy()).mean()) else: sub_ndfb=ndfb[i-n:i] sub_ndfb_withoutNaN=sub_ndfb[pd.notnull((sub_ndfb["value"]))]["value"] movingaverage2.append((sub_ndfb_withoutNaN.copy()).mean()) #确定顺序 astation=[] bstation=[] nlist=[] c=0 d=0 e=0 for i in df["group"]: if i=="a": astation.append(c) else: bstation.append(c) c+=1 for i in range(0,len1+len2): if i in astation: nlist.append(movingaverage1[d]) d+=1 else: nlist.append(movingaverage2[e]) e+=1 flist=pd.Series(nlist) print(flist)

这段代码实现了对DataFrame中按照"group"分组后，对"value"一列进行滑动平均的计算，并将计算结果存储在两个列表中（分别对应两个不同的"group"）。

首先，将DataFrame按照"group"分成两个子集ndfa和ndfb。然后，分别对这两个子集的"value"一列计算滑动平均，计算方式是每次向前移动1个单位进行平均，如果当前位置与之前的(n-1)个位置有nan值，则将平均值设为0。最终，将每次计算的结果存储在两个不同的列表中，分别对应两个不同的"group"。

相关问题

import pandas as pd import pyecharts.options as opts from pyecharts.charts import Bar, Line from pyecharts.render import make_snapshot from snapshot_selenium import snapshot as driver x_data = ["1月", "2月", "3月", "4月", "5月", "6月", "7月", "8月", "9月", "10月", "11月", "12月"] # 导入数据 df = pd.read_csv('E:/pythonProject1/第8章实验数据/beijing_AQI_2018.csv') attr = df['Date'].tolist() v1 = df['AQI'].tolist() v2=df['PM'].tolist() # 对AQI进行求平均值 data={'Date':pd.to_datetime(attr),'AQI':v1} df1 = pd.DataFrame(data) total=df1['AQI'].groupby([df1['Date'].dt.strftime('%m')]).mean() d1=total.tolist() y1=[] for i in d1: y1.append(int(i)) # print(d1) # print(y1) # 对PM2.5求平均值 data1={'Date':pd.to_datetime(attr),'PM':v2} df2 = pd.DataFrame(data1) total1=df2['PM'].groupby([df2['Date'].dt.strftime('%m')]).mean() d2=total1.tolist() y2=[] for i in d2: y2.append(int(i)) # print(d2) bar = ( Bar() .add_xaxis(xaxis_data=x_data) .add_yaxis( series_name="PM2.5", y_axis=y2, label_opts=opts.LabelOpts(is_show=False), color="#5793f3" ) .extend_axis( yaxis=opts.AxisOpts( name="平均浓度", type_="value", min_=0, max_=150, interval=30, axislabel_opts=opts.LabelOpts(formatter="{value}"), ) ) .set_global_opts( tooltip_opts=opts.TooltipOpts( is_show=True, trigger="axis", axis_pointer_type="cross" ), xaxis_opts=opts.AxisOpts( type_="category", axispointer_opts=opts.AxisPointerOpts(is_show=True, type_="shadow"), ), ) ) line = ( Line() .add_xaxis(xaxis_data=x_data) .add_yaxis( series_name="AQI", yaxis_index=1, y_axis=y1, label_opts=opts.LabelOpts(is_show=False), color='rgb(192,0, 0,0.2)' ) ) bar.overlap(line).render("five.html") bar.options.update(backgroundColor="#F7F7F7")

这段代码的功能是读取一个 csv 文件，分别计算 AQI 和 PM2.5 的每月平均值，并将它们分别用柱状图和折线图展示在同一个图表中。其中，柱状图表示 PM2.5，折线图表示 AQI，两者共用 x 轴（月份），而 y 轴分别是 PM2.5 的浓度和 AQI 的值。此外，折线图的 y 轴是右侧的另一个坐标轴。最后，将图表保存为 HTML 文件 five.html。

import pandas as pd import math as mt import numpy as np from sklearn.model_selection import train_test_split from Recommenders import SVDRecommender triplet_dataset_sub_song_merged = triplet_dataset_sub_song_mergedpd triplet_dataset_sub_song_merged_sum_df = triplet_dataset_sub_song_merged[['user','listen_count']].groupby('user').sum().reset_index() triplet_dataset_sub_song_merged_sum_df.rename(columns={'listen_count':'total_listen_count'},inplace=True) triplet_dataset_sub_song_merged = pd.merge(triplet_dataset_sub_song_merged,triplet_dataset_sub_song_merged_sum_df) triplet_dataset_sub_song_merged['fractional_play_count'] = triplet_dataset_sub_song_merged['listen_count']/triplet_dataset_sub_song_merged small_set = triplet_dataset_sub_song_merged user_codes = small_set.user.drop_duplicates().reset_index() song_codes = small_set.song.drop_duplicates().reset_index() user_codes.rename(columns={'index':'user_index'}, inplace=True) song_codes.rename(columns={'index':'song_index'}, inplace=True) song_codes['so_index_value'] = list(song_codes.index) user_codes['us_index_value'] = list(user_codes.index) small_set = pd.merge(small_set,song_codes,how='left') small_set = pd.merge(small_set,user_codes,how='left') mat_candidate = small_set[['us_index_value','so_index_value','fractional_play_count']] data_array = mat_candidate.fractional_play_count.values row_array = mat_candidate.us_index_value.values col_array = mat_candidate.so_index_value.values data_sparse = coo_matrix((data_array, (row_array, col_array)),dtype=float) K=50 urm = data_sparse MAX_PID = urm.shape[1] MAX_UID = urm.shape[0] recommender = SVDRecommender(K) U, S, Vt = recommender.fit(urm) Compute recommendations for test users uTest = [1,6,7,8,23] uTest_recommended_items = recommender.recommend(uTest, urm, 10) Output recommended songs in a dataframe recommendations = pd.DataFrame(columns=['user','song', 'score','rank']) for user in uTest: rank = 1 for song_index in uTest_recommended_items[user, 0:10]: song = small_set.loc[small_set['so_index_value'] == song_index].iloc[0] # Get song details recommendations = recommendations.append({'user': user, 'song': song['title'], 'score': song['fractional_play_count'], 'rank': rank}, ignore_index=True) rank += 1 display(recommendations)这段代码报错了，为什么？给出修改后的 代码

代码中的错误是使用了未定义的模块和类。需要先安装相应的模块并导入相应的类。

以下是修改后的代码：

import pandas as pd 
import numpy as np 
from scipy.sparse import coo_matrix 
from sklearn.model_selection import train_test_split 
from Recommenders.SVDRecommender import SVDRecommender # 导入SVDRecommender类

triplet_dataset_sub_song_merged = pd.read_csv('triplet_dataset_sub_song_merged.csv') # 读取数据
triplet_dataset_sub_song_merged_sum_df = triplet_dataset_sub_song_merged[['user','listen_count']].groupby('user').sum().reset_index() 
triplet_dataset_sub_song_merged_sum_df.rename(columns={'listen_count':'total_listen_count'},inplace=True) 
triplet_dataset_sub_song_merged = pd.merge(triplet_dataset_sub_song_merged,triplet_dataset_sub_song_merged_sum_df) 
triplet_dataset_sub_song_merged['fractional_play_count'] = triplet_dataset_sub_song_merged['listen_count']/triplet_dataset_sub_song_merged['total_listen_count'] 

small_set = triplet_dataset_sub_song_merged[['user','song','fractional_play_count']] 
user_codes = small_set.user.drop_duplicates().reset_index() 
song_codes = small_set.song.drop_duplicates().reset_index() 
user_codes.rename(columns={'index':'user_index'}, inplace=True) 
song_codes.rename(columns={'index':'song_index'}, inplace=True) 
song_codes['so_index_value'] = list(song_codes.index) 
user_codes['us_index_value'] = list(user_codes.index) 
small_set = pd.merge(small_set,song_codes,how='left') 
small_set = pd.merge(small_set,user_codes,how='left') 
mat_candidate = small_set[['us_index_value','so_index_value','fractional_play_count']] 
data_array = mat_candidate.fractional_play_count.values 
row_array = mat_candidate.us_index_value.values 
col_array = mat_candidate.so_index_value.values 
data_sparse = coo_matrix((data_array, (row_array, col_array)),dtype=float) 

K=50 
urm = data_sparse 
MAX_PID = urm.shape[1] 
MAX_UID = urm.shape[0] 

recommender = SVDRecommender(K) # 创建SVD推荐器
U, S, Vt = recommender.fit(urm) # 训练推荐器

uTest = [1,6,7,8,23] 
uTest_recommended_items = recommender.recommend(uTest, urm, 10) 

# 输出推荐结果
recommendations = pd.DataFrame(columns=['user','song', 'score','rank']) 
for user in uTest: 
    rank = 1 
    for song_index in uTest_recommended_items[user, 0:10]: 
        song = small_set.loc[small_set['so_index_value'] == song_index].iloc[0] 
        recommendations = recommendations.append({'user': user, 'song': song['song'], 'score': song['fractional_play_count'], 'rank': rank}, ignore_index=True) 
        rank += 1 

display(recommendations)